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Publisher: Elsevier   (Total: 3168 journals)

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Showing 1 - 200 of 3168 Journals sorted alphabetically
Academic Pediatrics     Hybrid Journal   (Followers: 39, SJR: 1.655, CiteScore: 2)
Academic Radiology     Hybrid Journal   (Followers: 26, SJR: 1.015, CiteScore: 2)
Accident Analysis & Prevention     Partially Free   (Followers: 105, SJR: 1.462, CiteScore: 3)
Accounting Forum     Hybrid Journal   (Followers: 28, SJR: 0.932, CiteScore: 2)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 42, SJR: 1.771, CiteScore: 3)
Achievements in the Life Sciences     Open Access   (Followers: 7)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 6)
Acta Astronautica     Hybrid Journal   (Followers: 453, SJR: 0.758, CiteScore: 2)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Biomaterialia     Hybrid Journal   (Followers: 30, SJR: 1.967, CiteScore: 7)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 3)
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 11, SJR: 0.18, CiteScore: 1)
Acta Histochemica     Hybrid Journal   (Followers: 5, SJR: 0.661, CiteScore: 2)
Acta Materialia     Hybrid Journal   (Followers: 330, SJR: 3.263, CiteScore: 6)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.504, CiteScore: 1)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.542, CiteScore: 1)
Acta Oecologica     Hybrid Journal   (Followers: 12, SJR: 0.834, CiteScore: 2)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription  
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 2, SJR: 0.307, CiteScore: 0)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 2, SJR: 1.793, CiteScore: 6)
Acta Poética     Open Access   (Followers: 4, SJR: 0.101, CiteScore: 0)
Acta Psychologica     Hybrid Journal   (Followers: 26, SJR: 1.331, CiteScore: 2)
Acta Sociológica     Open Access   (Followers: 1)
Acta Tropica     Hybrid Journal   (Followers: 7, SJR: 1.052, CiteScore: 2)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 3, SJR: 0.374, CiteScore: 1)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 2)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 3, SJR: 0.344, CiteScore: 1)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 1)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 7, SJR: 0.19, CiteScore: 0)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 3)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 8)
Acute Pain     Full-text available via subscription   (Followers: 15, SJR: 2.671, CiteScore: 5)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.53, CiteScore: 4)
Addictive Behaviors     Hybrid Journal   (Followers: 18, SJR: 1.29, CiteScore: 3)
Addictive Behaviors Reports     Open Access   (Followers: 9, SJR: 0.755, CiteScore: 2)
Additive Manufacturing     Hybrid Journal   (Followers: 13, SJR: 2.611, CiteScore: 8)
Additives for Polymers     Full-text available via subscription   (Followers: 23)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 196, SJR: 4.09, CiteScore: 13)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 12, SJR: 1.167, CiteScore: 4)
Advanced Powder Technology     Hybrid Journal   (Followers: 17, SJR: 0.694, CiteScore: 3)
Advances in Accounting     Hybrid Journal   (Followers: 9, SJR: 0.277, CiteScore: 1)
Advances in Agronomy     Full-text available via subscription   (Followers: 17, SJR: 2.384, CiteScore: 5)
Advances in Anesthesia     Full-text available via subscription   (Followers: 30, SJR: 0.126, CiteScore: 0)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 12, SJR: 0.992, CiteScore: 1)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 12, SJR: 1.551, CiteScore: 4)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 24, SJR: 2.089, CiteScore: 5)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 15, SJR: 0.572, CiteScore: 2)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.61, CiteScore: 7)
Advances in Botanical Research     Full-text available via subscription   (Followers: 1, SJR: 0.686, CiteScore: 2)
Advances in Cancer Research     Full-text available via subscription   (Followers: 35, SJR: 3.043, CiteScore: 6)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 1.453, CiteScore: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 1.992, CiteScore: 5)
Advances in Cell Aging and Gerontology     Full-text available via subscription   (Followers: 5)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 14)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 29, SJR: 0.156, CiteScore: 1)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 11, SJR: 0.713, CiteScore: 1)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 11, SJR: 1.316, CiteScore: 2)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 26, SJR: 1.562, CiteScore: 3)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 20, SJR: 1.977, CiteScore: 8)
Advances in Computers     Full-text available via subscription   (Followers: 14, SJR: 0.205, CiteScore: 1)
Advances in Dermatology     Full-text available via subscription   (Followers: 16)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 13)
Advances in Digestive Medicine     Open Access   (Followers: 12)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 7)
Advances in Drug Research     Full-text available via subscription   (Followers: 26)
Advances in Ecological Research     Full-text available via subscription   (Followers: 44, SJR: 2.524, CiteScore: 4)
Advances in Engineering Software     Hybrid Journal   (Followers: 29, SJR: 1.159, CiteScore: 4)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 8)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 52, SJR: 5.39, CiteScore: 8)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 1)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 67, SJR: 0.591, CiteScore: 2)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Genetics     Full-text available via subscription   (Followers: 21, SJR: 1.354, CiteScore: 4)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11, SJR: 12.74, CiteScore: 13)
Advances in Geophysics     Full-text available via subscription   (Followers: 7, SJR: 1.193, CiteScore: 3)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 26, SJR: 0.368, CiteScore: 1)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 11, SJR: 0.749, CiteScore: 3)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 3, SJR: 0.193, CiteScore: 0)
Advances in Immunology     Full-text available via subscription   (Followers: 37, SJR: 4.433, CiteScore: 6)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 10, SJR: 1.163, CiteScore: 2)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 2, SJR: 1.938, CiteScore: 3)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6, SJR: 0.176, CiteScore: 0)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 3)
Advances in Life Course Research     Hybrid Journal   (Followers: 9, SJR: 0.682, CiteScore: 2)
Advances in Lipobiology     Full-text available via subscription   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Marine Biology     Full-text available via subscription   (Followers: 21, SJR: 0.88, CiteScore: 2)
Advances in Mathematics     Full-text available via subscription   (Followers: 15, SJR: 3.027, CiteScore: 2)
Advances in Medical Sciences     Hybrid Journal   (Followers: 9, SJR: 0.694, CiteScore: 2)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 5, SJR: 1.158, CiteScore: 3)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 25)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 8)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.182, CiteScore: 0)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 5)
Advances in Oncobiology     Full-text available via subscription   (Followers: 2)
Advances in Organ Biology     Full-text available via subscription   (Followers: 2)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18, SJR: 1.875, CiteScore: 4)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.174, CiteScore: 0)
Advances in Parasitology     Full-text available via subscription   (Followers: 5, SJR: 1.579, CiteScore: 4)
Advances in Pediatrics     Full-text available via subscription   (Followers: 27, SJR: 0.461, CiteScore: 1)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 19)
Advances in Pharmacology     Full-text available via subscription   (Followers: 17, SJR: 1.536, CiteScore: 3)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 0.574, CiteScore: 1)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.109, CiteScore: 1)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 11)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 6)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20, SJR: 0.791, CiteScore: 2)
Advances in Psychology     Full-text available via subscription   (Followers: 68)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6, SJR: 0.371, CiteScore: 1)
Advances in Radiation Oncology     Open Access   (Followers: 3, SJR: 0.263, CiteScore: 1)
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 3, SJR: 0.101, CiteScore: 0)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 6)
Advances in Space Research     Full-text available via subscription   (Followers: 435, SJR: 0.569, CiteScore: 2)
Advances in Structural Biology     Full-text available via subscription   (Followers: 5)
Advances in Surgery     Full-text available via subscription   (Followers: 13, SJR: 0.555, CiteScore: 2)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 37, SJR: 2.208, CiteScore: 4)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 20)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 15)
Advances in Virus Research     Full-text available via subscription   (Followers: 6, SJR: 2.262, CiteScore: 5)
Advances in Water Resources     Hybrid Journal   (Followers: 55, SJR: 1.551, CiteScore: 3)
Aeolian Research     Hybrid Journal   (Followers: 6, SJR: 1.117, CiteScore: 3)
Aerospace Science and Technology     Hybrid Journal   (Followers: 394, SJR: 0.796, CiteScore: 3)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.42, CiteScore: 2)
African J. of Emergency Medicine     Open Access   (Followers: 6, SJR: 0.296, CiteScore: 0)
Ageing Research Reviews     Hybrid Journal   (Followers: 12, SJR: 3.671, CiteScore: 9)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 489, SJR: 1.238, CiteScore: 3)
Agri Gene     Hybrid Journal   (Followers: 1, SJR: 0.13, CiteScore: 0)
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 18, SJR: 1.818, CiteScore: 5)
Agricultural Systems     Hybrid Journal   (Followers: 32, SJR: 1.156, CiteScore: 4)
Agricultural Water Management     Hybrid Journal   (Followers: 45, SJR: 1.272, CiteScore: 3)
Agriculture and Agricultural Science Procedia     Open Access   (Followers: 4)
Agriculture and Natural Resources     Open Access   (Followers: 3)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 58, SJR: 1.747, CiteScore: 4)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.589, CiteScore: 3)
Air Medical J.     Hybrid Journal   (Followers: 8, SJR: 0.26, CiteScore: 0)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.19, CiteScore: 0)
Alcohol     Hybrid Journal   (Followers: 12, SJR: 1.153, CiteScore: 3)
Alcoholism and Drug Addiction     Open Access   (Followers: 12)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 2, SJR: 0.604, CiteScore: 3)
Alexandria J. of Medicine     Open Access   (Followers: 1, SJR: 0.191, CiteScore: 1)
Algal Research     Partially Free   (Followers: 11, SJR: 1.142, CiteScore: 4)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.504, CiteScore: 1)
Allergology Intl.     Open Access   (Followers: 5, SJR: 1.148, CiteScore: 2)
Alpha Omegan     Full-text available via subscription   (SJR: 3.521, CiteScore: 6)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 11, SJR: 0.201, CiteScore: 1)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 54, SJR: 4.66, CiteScore: 10)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 6, SJR: 1.796, CiteScore: 4)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 6, SJR: 1.108, CiteScore: 3)
Ambulatory Pediatrics     Hybrid Journal   (Followers: 5)
American Heart J.     Hybrid Journal   (Followers: 58, SJR: 3.267, CiteScore: 4)
American J. of Cardiology     Hybrid Journal   (Followers: 67, SJR: 1.93, CiteScore: 3)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 47, SJR: 0.604, CiteScore: 1)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 13)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 14, SJR: 1.524, CiteScore: 3)
American J. of Human Genetics     Hybrid Journal   (Followers: 37, SJR: 7.45, CiteScore: 8)
American J. of Infection Control     Hybrid Journal   (Followers: 29, SJR: 1.062, CiteScore: 2)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 37, SJR: 2.973, CiteScore: 4)
American J. of Medicine     Hybrid Journal   (Followers: 50)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3, SJR: 1.967, CiteScore: 2)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 277, SJR: 2.7, CiteScore: 4)
American J. of Ophthalmology     Hybrid Journal   (Followers: 66, SJR: 3.184, CiteScore: 4)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 5, SJR: 0.265, CiteScore: 0)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.289, CiteScore: 1)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, CiteScore: 1)
American J. of Pathology     Hybrid Journal   (Followers: 32, SJR: 2.139, CiteScore: 4)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 28, SJR: 2.164, CiteScore: 4)
American J. of Surgery     Hybrid Journal   (Followers: 39, SJR: 1.141, CiteScore: 2)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.767, CiteScore: 1)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 7)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.144, CiteScore: 3)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 67, SJR: 0.138, CiteScore: 0)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 25, SJR: 0.411, CiteScore: 1)
Anales de Cirugia Vascular     Full-text available via subscription   (Followers: 1)
Anales de Pediatría     Full-text available via subscription   (Followers: 3, SJR: 0.277, CiteScore: 0)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription  
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 5, SJR: 4.849, CiteScore: 10)
Analytica Chimica Acta     Hybrid Journal   (Followers: 44, SJR: 1.512, CiteScore: 5)
Analytica Chimica Acta : X     Open Access  
Analytical Biochemistry     Hybrid Journal   (Followers: 221, SJR: 0.633, CiteScore: 2)
Analytical Chemistry Research     Open Access   (Followers: 13, SJR: 0.411, CiteScore: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 14)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 2)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 25, SJR: 0.683, CiteScore: 2)
Angiología     Full-text available via subscription   (SJR: 0.121, CiteScore: 0)
Angiologia e Cirurgia Vascular     Open Access   (Followers: 1, SJR: 0.111, CiteScore: 0)
Animal Behaviour     Hybrid Journal   (Followers: 233, SJR: 1.58, CiteScore: 3)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 7, SJR: 0.937, CiteScore: 2)
Animal Reproduction Science     Hybrid Journal   (Followers: 7, SJR: 0.704, CiteScore: 2)

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Similar Journals
Journal Cover
Analytica Chimica Acta
Journal Prestige (SJR): 1.512
Citation Impact (citeScore): 5
Number of Followers: 44  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0003-2670 - ISSN (Online) 1873-4324
Published by Elsevier Homepage  [3168 journals]
  • Reshaping of Pipette Tip: A Facile and Practical Strategy for Sorbent
           Packing-Free Solid Phase Extraction
    • Abstract: Publication date: Available online 30 November 2019Source: Analytica Chimica ActaAuthor(s): Shuangshou Wang, Zhendong He, Wenzhi Li, Jiayi Zhao, Tong Chen, Shimin Shao, Hongmei ChenPipette tip-based solid phase extraction (PT-SPE) has been proved to be an effective and user-friendly separation technique due to its miniaturized procedure and practical convenience. However, the vast majority of existing PT-SPE devices consist of a filter-sorbents-filter sandwich structure, which may suffer the unforeseen risk of sorbents leakage caused by the looseness of filters. More importantly, many high-capacity nanosorbents with particle size smaller than pore size of filters are unavailable. Thus, sorbent packing-free and sample low-consumption PT-SPE could be a more robust strategy for separation and detection, but such a possibility has not been explored yet. Herein we report a tubing reshaping strategy for facile fabrication of sorbent packing-free PT-SPE devices. Three types of reshaped PTs, namely stretched tube-like, self-crimping and filter in-built PTs, were fabricated via simple heating and stretching operations. The reshaped PTs exhibited flexible surface chemical post-modification. The SPE process was directly performed in reshaped PTs with an obviously enhanced extraction efficiency compared to once-shaping PTs while no need of packing sorbents. Extraction of nucleosides from human urine by boronic acid-functionalized reshaped PTs was demonstrated. Our findings technically renovate the structural composition of PT-SPE devices. As PTs are inexpensive and high-plasticity, the sorbent packing-free SPE scheme presented herein could find more promising applications and provides a new perspective for design and fabrication of novel sorbent packing-free SPE devices.Graphical abstractImage 1
       
  • A Facile Microfluidic Paper-based Analytical Device for
           Acetylcholinesterase Inhibition Assay Utilizing Organic Solvent Extraction
           in Rapid Detection of Pesticide Residues in Food
    • Abstract: Publication date: Available online 30 November 2019Source: Analytica Chimica ActaAuthor(s): Lili Jin, Zhenxia Hao, Qinqin Zheng, Hongping Chen, Li Zhu, Chen Wang, Xin Liu, Chengyin LuThe incompatibility of most organic solvents with acetylcholinesterase (AChE) inhibition assay normally limits pesticide extraction efficiency in sample pretreatment, which might cause false negatives in real world sample assessment. Herein, a novel method has been developed for an improved AChE inhibition assay via organic solvent extraction combined spontaneous in situ solvent evaporation on microfluidic paper-based analytical devices. Enzyme pre-immobilization procedure was spared and AChE was added to the system after sampling step until a complete in-situ solvent evaporation process was performed on chip. IC50 levels of the six investigated organophosphate and carbamates pesticides indicated a completely eliminated influence of solvents on AChE behavior with the new method. Most importantly, analytical performances were significantly improved in food sample measurements. Reduction in matrix effect was observed when acetonitrile was adopted for lettuce sample pretreatment instead of water. Studies on different pesticides suggested a remarkably decreased discrimination effect on recoveries from sample pretreatment with the new developed method. The recovery level for phoxim spiked head lettuce samples reached (107.5±14.2) %, in comparison with that of (18.6±1.4) % from water-based extraction. Spiked water and apple juice samples with carbaryl concentration of as low as 0.02 mg L-1 were also successfully recognized with the present method by visual detection. This is the first report on direct sampling of organic extracts for AChE inhibition assay on-chip and it might provide a new perspective for real world sample assessments involving bio-reagents.Graphical abstractImage 1
       
  • Electrochemiluminescence aptasensor for multiple determination of Hg2+ and
           Pb2+ ions by using the MIL-53(Al)@CdTe-PEI modified electrode
    • Abstract: Publication date: Available online 30 November 2019Source: Analytica Chimica ActaAuthor(s): Defen Feng, Penghui Li, Xuecai Tan, Yeyu Wu, Fucun Wei, Fangkai Du, Chenhao Ai, Yanni Luo, Quanyou Chen, Heyou HanAn aptasensor based on MIL-53(Al)@CdTe was designed for multiple determination of Hg2+ and Pb2+ by electrochemiluminescence (ECL). Upon the recognition of Hg2+, aptamer 2-AuNPs form hairpin structures and are removed from the electrode. While in the presence of Pb2+, aptamer 1-PtNPs capture the target ions and form G-quadruplexes, and then bring PtNPs close enough to CdTe QDs to produce ECL resonance energy transfer. Upon aptamer interaction with Hg2+ and Pb2+, decreased ECL intensity was observed due to enhanced resonance energy transfer (ERET) and attenuated surface plasmon resonance (SPR). The ECL intensity difference (ΔECL) could therefore be used to detect heavy-metal ions with detection limits of 4.1 × 10-12 M (path 1, Hg2+), 3.7 × 10-11 M (path 2, Pb2+), and 2.4 × 10-11 M (path 3, Pb2+). The aptasensor could also be used for detecting Hg2+ and Pb2+ in fish and shrimp samples with good recoveries.Graphical abstractImage 1
       
  • A novel immunochromatographic assay using ultramarine blue particles as
           visible label for quantitative detection of hepatitis B virus surface
           antigen
    • Abstract: Publication date: Available online 29 November 2019Source: Analytica Chimica ActaAuthor(s): Jing Liu, Qiongqiong Yu, Guangying Zhao, Wenchao DouUltramarine blue particles as a novel visible label has been used to develop immunochromatographic assay (ICA). The ultramarine blue particles, as a sodalite mineral with formula: (Na,Ca)8[(S,Cl,SO4,OH)2(Al6Si6O24)], can generate a blue visible signal were used as a label for ICA. Ultramarine blue particles were applied to a sandwich immunoassay to detect hepatitis B virus surface antigen (HBsAg). Ultramarine blue particles were separated from ultramarine blue industrial product by centrifugation. The polyacrylic acid (PAA) was used to modify the carboxyl group on the surface of ultramarine blue particles. The goat anti-HBsAg monoclonal antibody was modified on ultramarine blue particles by EDC/NHS activation of the carboxyl groups. In the presence of HBsAg, the immune ultramarine blue particles were bound on test line zone and forming a blue line on ICA strip which was directly readout by naked eye and quantitatively measured by Image J software. Under optimal conditions, the color depth of test line was linearly correlated with the concentration of HBsAg in concentration range from 1 to 50 ng mL-1. The calibration equation was y = 385.796 + 97.2298x (R2 = 0.9872), with limit of detection (LOD) of 0.37 ng mL -1(S/N = 3). The sensitivity of this novel ICA was better than that of ICA based on traditional gold nanoparticles as reporter probe. The ultramarine blue particles offer an alternative type of visible label nanomaterial for the development of ICA.Graphical abstractSchematic illustration of preparation of antibody modified ultramarine blue particles and the principle of qualitative detection strategy of hepatitis B virus surface antigen (HBsAg) with an immunochromatographic assay.Image 1
       
  • READ-BY-EYE quantification of aluminum (III) IN distance-based
           microfluidic paper-based analytical devices
    • Abstract: Publication date: Available online 29 November 2019Source: Analytica Chimica ActaAuthor(s): Michael P. Nguyen, Sydney P. Kelly, John B. Wydallis, Charles S. HenryHerein we report the first two distance-based microfluidic paper-based analytical devices (μPADs) using fluorescence to quantify aluminum. In addition to their read-by-eye quantification, the devices are simple to fabricate, require no sample pretreatment or preconcentration, and have a shelf life of>5 months. The first device is designed in a “chemometer” format where the length of a fluorescent band linearly responds to an Al(III) concentration. The second device uses a radial design where the fluorescent diameter also linearly responds to an Al(III) concentration. The chemometer device has a detection limit of 2.5 ppm (100 μM) and a linear range from 2–54 ppm Al(III) (100 μM–1 mM), R2 = 0.989). The radial device has a detection limit of 0.9 ppm (33 μM) and a linear range from 2–24 ppm Al(III) (100–900 μM, R2 = 0.968). The utility of the μPADs were successfully demonstrated by measuring Al(III) in two water effluent samples from the Gold King Mine near Silverton, CO.Graphical abstractImage 1
       
  • Molybdenum sulfide-based electrochemical platform for high sensitive
           detection of taxifolin in Chinese medicine
    • Abstract: Publication date: Available online 29 November 2019Source: Analytica Chimica ActaAuthor(s): Xia Zhang, Danqing Li, Chaoyang Dong, Jianguo shi, Yangang Sun, Baoxian Ye, Yuandong XuMoS2 and nitrogen doped active carbon composite (MoS2/ANC) is fabricated to detect taxifolin and exhibits superior redox current response and decreased redox potential difference. Further investigation reveals that the kinetic process of the redox reaction of taxifolin on MoS2/ANC electrode is controlled by both adsorption and diffusion process. Under the optimum conditions, the redox peak currents linearly relate with the concentration of taxifolin in the range of 1×10-9∼1×10-6 mol L-1, accompanied by the low detection limit (3×10-10 mol L-1). Meanwhile, outstanding selectivity, stability and repeatability are also obtained at MoS2/ANC electrode. At last, the proposed method is applied to quantitatively detect taxifolin in fructus polygoni orientalis and satisfactory results have been achieved.Graphical abstractImage 1
       
  • Sepsis progression monitoring via human serum fibronectin detection based
           on sandwich-type electrochemical immunosensor
    • Abstract: Publication date: Available online 29 November 2019Source: Analytica Chimica ActaAuthor(s): Hui-Yun Tian, Jin-Yuan Chen, Jia Lin, Qi-Rui Liang, Yun Lei, Xin Li, Yong Wu, Liang-Yong Yang, Xin-Hua Lin, Ai-Lin Liu, Yuan-Zhong ChenSepsis has always been a severe clinical problem in critical care medicine due to its rather high mortality and poor prognosis. The current study reported for the first time a practical immunosensor for fibronectin (FN) detection in human serum by electrochemistry. A simple but robust sandwich-type strategy was employed without any complex design or material modifications, which exhibited a linear calibration plot over the 15.625-500 ng/mL concentration range and a detection limit of 15 ng/mL. The results showed that the proposed strategy displayed an excellent selectivity against other non-target substances in human serum, a higher accuracy and a better stability when compared with the traditional enzyme-linked immunosorbent assay (ELISA) in detecting the same or mixed serum from 21 healthy subjects. Furthermore, the proposed electrochemical immunosensor successfully monitored the level of serum FN at various time points in five septic patients during the treatment. These findings demonstrate that the proposed strategy is highly sensitive and accurate in monitoring sepsis progress and has significant clinical improvements over the ELISA methodology, signifying a great potential of a commercial kit.Graphical abstractImage 1
       
  • A simple equipment and colorimetric method for determination of chloroform
           in water
    • Abstract: Publication date: Available online 28 November 2019Source: Analytica Chimica ActaAuthor(s): Masoud Shariati-Rad, Fariba FattahiChlorination is a common and successful method for disinfection of water all around the world, especially in developing countries. However, this process can produce trihalomethanes (THMs) byproducts which are carcinogen. The major THM occurring in this process is chloroform. The purpose of this study was to design a simple equipment for colorimetric determination of chloroform in various water samples. The method is based on the colorimetric reaction of chloroform with resorcinol in strong basic medium on a filter paper. Response surface methodology (RSM) was employed to optimize the determination condition. The reagents were immobilized on filter paper and the color change was followed to quantify chloroform without using any analytical instrument. Detection limit and linear range of the proposed method were 0.007 mg/L and 0.011-1.192 mg/L, respectively for analysis of samples with volume of 2.0 L. The method was successfully applied to determine chloroform in different water samples and compared with GC-MS as a standard method. Employing the designed device, purge, trap and analysis steps were performed in a single run which can reduce the uncertainties originated by excessive steps of the analysis.Graphical abstractImage 1
       
  • Using single-particle ICP-MS for unravelling the effect of type of food on
           the physicochemical properties and gastrointestinal stability of ZnONPs
           released from packaging materials
    • Abstract: Publication date: Available online 28 November 2019Source: Analytica Chimica ActaAuthor(s): Beatriz Gomez-Gomez, Ma Teresa Perez-Corona, Yolanda MadridABSTRACTThis article discusses the application of Single-Particle Inductively Coupled Plasma Mass Spectrometry (SP-ICP-MS) to study the effect of different types of food (orange juice and chicken breast) on the fate of zinc oxide nanoparticles (ZnONPs) migrated from two widely employed food packaging materials (polyethylene terephthalate (PET) and low density polyethylene (LDPE)). The gastrointestinal stability of ZnONPs was also evaluated. The idea behind this study is to track for first time the transformations underwent of nanoparticles in the different steps of their route from packaging to the consumer. The presence of high amount of dissolved zinc in the samples notably influenced size detection limit and the accuracy of SP-ICP-MS measurements. The diameter limits of detection (LODd) were 26 nm, 95 nm, 108 nm and 129 nm for aqueous solution, chicken breast extract and for oral and intestinal extracts, respectively. ZnONPs characterization in juice was not possible with SP-ICP-MS due to nanoparticles size was below LODd. Besides difficulties, SP-ICP-MS after extraction with Tris-HCl allowed us to determine that a 72% of the ZnONPs that migrated to chicken breast were smaller than 95 nm. Complementary to SP-ICP-MS, transmission electron microscopy (TEM) enabled to detect small nanoparticles (
       
  • Chemometric challenges in development of paper-based analytical devices:
           optimization and image processing
    • Abstract: Publication date: Available online 28 November 2019Source: Analytica Chimica ActaAuthor(s): Vahid Hamedpour, Paolo Oliveri, Riccardo Leardi, Daniel CitterioAlthough microfluidic paper-based analytical devices (μPADs) get a lot of attention in the scientific literature, they rarely reach the level of commercialization. One possible reason for this is a lack of application of machine learning techniques supporting the design, optimization and fabrication of such devices. This work demonstrates the potential of two chemometric techniques including design of experiments (DoE) and digital image processing to support the production of μPADs. On the example of a simple colorimetric assay for isoniazid relying on the protonation equilibrium of methyl orange, the experimental conditions were optimized using a D-optimal design (DO) and the impact of multiple factors on the μPAD response was investigated. In addition, this work demonstrates the impact of automatic image processing on accelerating color value analysis and on minimizing errors caused by manual detection area selection. The employed algorithm is based on morphological recognition and allows the analysis of RGB (red, green, and blue) values in a repeatable way. In our belief, DoE and digital image processing methodologies are keys to overcome some of the remaining weaknesses in μPAD development to facilitate their future market entry.Graphical abstractImage 1
       
  • An efficient TP-FRET-based lysosome-targetable fluorescent probe for
           imaging peroxynitrite with two well-resolved emission channels in living
           cells, tissues and zebrafish
    • Abstract: Publication date: Available online 28 November 2019Source: Analytica Chimica ActaAuthor(s): Shuguo Sun, Haiyuan Ding, Gangqiang Yuan, Liyi ZhouPeroxynitrite (ONOO-), an important role of reactive oxygen species (ROS) in vivo, and studies showed abnormal of ROS can induce lysosomal membrane permeabilization (LMP) and lead to the death of cells. Thus, it is of great significance for designing an effective method for investigating relationship between physiology and pathology between ONOO- and lysosome. Herein, for the first time, we adopted a Förster resonance energy transfer (FRET) strategy to construct a lysosome-targetable small molecular ratiometric two-photon (TP) fluorescent probe (NpRh-ONOO) for detecting ONOO- in living cells, tissues and zebrafish. Specifically, a TP fluorophore and a rhodamine B fluorophore are directly connected by a flexible piperidine linker to form the TP-FRET-scaffold, a hydrazide as ONOO- reactive set, and a dimethylamino as lysosome targeting-group, which shows a target-modulated ratiometric TP fluorescence response, two well-resolved emission peaks separated by 73 nm, rapid response (
       
  • Facile synthesis of guanidyl-based magnetic ionic covalent organic
           framework composites for selective enrichment of phosphopeptides
    • Abstract: Publication date: Available online 27 November 2019Source: Analytica Chimica ActaAuthor(s): Fangfang Xiong, Liyan Jiang, Qiong JiaABSTRACTProtein phosphorylation plays vital roles in the regulation of various biological processes involving in protein folding, molecular recognition, cell growth, and metabolism. It is prerequisite to develop effective enrichment methods of trace phosphopeptides before mass spectrometry (MS) analysis. In this study, we proposed a facile strategy to synthesize magnetic ionic covalent organic frameworks (Fe3O4@iCOFs) for the capture of phosphopeptides with guanidyl as the ionic ligand instead of the post-synthetic functionalization strategy. The developed Fe3O4@iCOFs contain a large amount of amino groups, positive charge, as well as owned superparamagnetism. The enrichment of phosphopeptides is based on the electrostatic interaction and hydrogen bonds formed between phosphate groups and guanidyl groups. By combing with MS determinations, high sensitivity of phosphopeptides (the lowest detection amount being 0.4 fmol) was achieved. The obtained material provided selective enrichment capacity of phosphopeptides from non-fat milk digest and HeLa cells, showing great potential in the detection of low-abundance phosphopeptides in complex real samples.Graphical abstractImage 1
       
  • Determination of 2,4,6-trinitrophenol by In-situ Assembly of SBA-15 with
           Multi-Hydroxyl Carbon Dots
    • Abstract: Publication date: Available online 27 November 2019Source: Analytica Chimica ActaAuthor(s): Xuechuan Wang, Xinjie Li, Xiao Li, Yansong Wang, Qingxin Han, Ji LiA novel composite fluorescent probe (SCDs) was synthesized by forming a covalent bond between mesoporous SBA-15 functionalized with 3-glycidyloxypropyltrimethoxysilane (SBA-15/560) and multi-hydroxyl carbon dots (CDs). The composite probe not only presented excellent fluorescence properties of multi-hydroxyl CDs but highly ordered structure of mesopores as well. Subsequently, the composite fluorescent probe was used for 2,4,6-trinitrophenol (TNP) detection. It was found that the composite fluorescent probe had a selective and sensitive response towards TNP. The results of the TNP assay show that the composite fluorescent probe exhibits two wide linear regions in the range of 1-8 and 10-70 μM with a low limit detection of 0.17 μM, which is lower than that of free CDs for TNP (0.3 μM). The analysis of real water samples confirmed that the composite probe could be used as a promising sensor for TNP detection.Graphical abstractImage 1
       
  • Label-free fluorescence “turn-on” strategy for mercury (II) detection
           based on the T-Hg2+-T configuration and the DNA-sensitized luminescence of
           terbium (III)
    • Abstract: Publication date: Available online 27 November 2019Source: Analytica Chimica ActaAuthor(s): Zhihong Li, Hongjing Sun, Xinyue Ma, Ruifang Su, Rui Sun, Chuanyu Yang, Chunyan SunA novel label-free fluorescence “turn-on” strategy was developed for the sensitive detection of Hg2+ based on the thymine-Hg2+-thymine (T-Hg2+-T) coordination and the fact that single-stranded DNA (ssDNA) greatly enhances the fluorescence of terbium (III) (Tb3+), but double-stranded DNA (dsDNA) does not. In the absence of Hg2+, the mercury-specific DNA (MSD) hybridized with the corresponding complementary strand (cDNA) to form a double helix structure in solution based on Watson-Crick base pairings, which cannot enhance the fluorescence of Tb3+. In the presence of Hg2+, MSD preferentially bound with Hg2+ to form the T-Hg2+-T complex due to the strong affinity of Hg(II) for the T bases of DNA, thus avoiding the hybridization of the cDNA to MSD. The free cDNA can greatly enhance the emission of Tb3+, leading to a sharp increase in fluorescence intensity. Under the optimized conditions, the increased fluorescence intensity was proportional to the concentration of Hg2+ in the range from 10 to 600 nM, and this method can detect concentrations of Hg2+ as low as 0.24 nM. Moreover, satisfactory results were obtained for the detection of Hg2+ in river water and fish samples, and the results were consistent with those from the atomic fluorescence spectroscopy (AFS). Thus, the fluorescence characteristics of Tb3+ were here used in a “turn on” approach to detect Hg2+, which represents a new opportunity for Hg2+ analysis in the field of environmental monitoring and food safety.Graphical abstractImage 1
       
  • Assembling Reduced Graphene Oxide with Sulfur/Nitrogen- “Hooks” for
           Electrochemical Determination of Hg(II)
    • Abstract: Publication date: Available online 27 November 2019Source: Analytica Chimica ActaAuthor(s): Cheng-Cheng Bi, Xu-Xu Ke, Xing Chen, Rohan Weerasooriya, Zhan-Yong Hong, Lian-Chao Wang, Yu-Cheng WuHerein the sulfur/nitrogen contained groups, serving as the “hooks” for electrochemical determination of Hg(II), were assembled on the reduced graphene oxide (hereafter SN-rGO) via a one-step facile hydrothermal method. The thiourea acts as a precursor for sulfur/nitrogen doping and partial reduction of graphene oxide. The SN-rGO was used to modify the glassy carbon electrode (GCE) for electrochemical detection of Hg(II) by square wave anodic stripping voltammetry (SWASV). The sulfur/nitrogen doping significantly improves the Hg(II) complexation by SN-rGO due to the creation of multifunctional groups on the graphene nanosheet. The SN-rGO modified electrode has excellent sensitivity (20.48 μA/μM) and limit of detection (LOD 8.93 nM) for Hg(II) detection. The newly developed Hg(II) sensing electrode possesses minimal interference for other ions typically found in natural waters. Therefore, it can be used for routine water quality monitoring. The fabrication of the SN-rGO electrode is rapid and low cost; hence, it offers a potential platform for environmental monitoring of toxic metal ions.Graphical abstractImage 1
       
  • A Streamlined Workflow for Twoplexing of N-linked Glycans Using Light
           (12C6) and Heavy (13C6) Isotopologues of 3-Aminobenzenesulfonic Acid
    • Abstract: Publication date: Available online 26 November 2019Source: Analytica Chimica ActaAuthor(s): Zoltan Szabo, Shaheer H. Khan, Philip J. Widdowson, Dietmar Reusch, Rosa Viner, Sara Carillo, Andreas Huhmer, Jonathan BonesComparative glycosylation analysis of biopharmaceuticals requires the development of methods that deliver the necessary throughput, support structural elucidation and relative quantitation of glycans released from therapeutics. The current study presents the development and applicability assessment of a twoplex approach using light and heavy isotopolouges of 3-aminobenzenesulfonic acid (3-ASA) under wet labeling conditions followed by UHPLC-MS analysis in data dependent acquisition mode. Excellent labelling efficiency,>90%, was achieved for both the light and heavy variants of the reagent. Glycan distributions of two human IgG lots labeled by light and heavy isotopolouges were identical, demonstrating no labeling bias introduced by either of the isotopologues. Peak area distributions of glycan profiles of two human IgG lots were compared to 2-aminobenzamide (2-AB) and RapiFluor-MS protocols. The comparison led to identical results in peak area distribution across the three dyes, but differences in chromatographic selectivity attributed to the different tags. MS1 based relative quantitation was further validated by releasing glycans from the same lot of human IgG, with glycan pools obtained labeled with light and heavy isotopologues separately, followed by mixing and clean-up of the same amount of light and heavy labeled glycan pools. MS analyses of each glycan resulted in a ratio of light and heavy XIC to be 0.97 ≤ x ≤ 1.05, demonstrating the method is amenable for the relative quantitation of glycans. Excellent correlation between the relative quantitation data of N-glycans from two human IgG N-glycan pools using the twoplex approach and ratios from peak area distribution calculated from the fluorescent chromatogram was observed (r=0.986), further corroborating the reliability of the method and its potential applicability in biopharmaceutical industry. Highly informative HCD-MS2 spectra dominated mostly by Y- and Z-type single and double glycosidic fragment ions facilitate structural interpretation of the oligosaccharides.Graphical abstractImage 1
       
  • CuO-ZnO heterojunction derived from Cu2+-doped ZIF-8: a new photoelectric
           material for ultrasensitive PEC immunoassay of CA125 with near-zero
           background noise
    • Abstract: Publication date: Available online 26 November 2019Source: Analytica Chimica ActaAuthor(s): Kang Zou, Yamin Fu, Ruiying Yang, Xiaohua Zhang, Cuicui Du, Jinhua ChenBy direct calcination of Cu2+-doped ZIF-8 in oxygen atmosphere, a new photoelectric material, CuO-ZnO heterojunction, was prepared. The morphology and structure were investigated in detail by several methods, such as scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption method and X-ray diffraction. Under visible light irradiation, CuO-ZnO heterojunction exhibits excellent PEC behavior in aqueous media with the presence of ascorbic acid (AA) and dissolved oxygen at -0.3 V. Taking the CA125-antibody functionalized CuO-ZnO heterojunction (CuO-ZnO-Ab2) as a signal source, a novel photoelectrochemical (PEC) immunosensing platform was developed for ultrasensitive assay of CA125. Because of the target-induced introduction of photoelectric material to the sensing platform, the proposed PEC immunosensor has excellent performance for CA125 assay: near-zero background noise, wide linear response range (1×10-5 U/mL to 100 U/mL) and low detection limit (3.16×10-6 U/mL). The developed CuO-ZnO heterojunction and the related PEC sensing platform may have promising applications in ultrasensitive and highly accurate monitoring of various proteins in bioanalysis and disease diagnosis.Graphical abstractImage 1
       
  • Visual Detection for Nucleic Acid-based Techniques as Potential On-site
           Detection Methods. A Review
    • Abstract: Publication date: Available online 26 November 2019Source: Analytica Chimica ActaAuthor(s): Mengyao Zhang, Jing Ye, Jin-song He, Fang Zhang, Jianfeng Ping, Cheng Qian, Jian WuNucleic acid-based techniques could achieve highly sensitive detection by amplifying template molecules to millions of folds. It has been one of the most valued analytical methods and is applied in many detection fields, such as diagnosis of infectious diseases, food safety assurance and so on. Nucleic acid-based techniques consist of three steps: nucleic acid extraction, amplification, and product detection. Among them, the detection step plays a vital role because it shows the results directly. As the trend of detection is simple, rapid and instrument-free, it is of necessity to carry out visual detection, where the result read-out could be visible and distinguished by the naked eye. In this critical review, advanced visual detection methods are summarized and discussed in detail, aiming to promote the potential application in on-site detection.Graphical abstractImage 1
       
  • Incorporation of Quantum Carbon Dots into a Zinc Oxide Hydrogel for use as
           an Effective Hexavalent Chromium Sensing Platform
    • Abstract: Publication date: Available online 24 November 2019Source: Analytica Chimica ActaAuthor(s): Adam Truskewycz, Sabrina A. Beker, Andrew S. Ball, Billy Murdoch, Ivan ColeHydrogels offer a unique medium for sensing applications as they can draw upon the benefits of both solid and liquid sensing platforms. Incorporation of functionalised fluorescent nanoparticles within the hydrogel matrix results in a three-dimensional nanocomposite capable of interacting with water-soluble analytes, facilitating quantitative sensing applications. Here, we report the synthesis of a novel Polyvinylpyrrolidone assembled hydrogel stabilised with zinc oxide quantum dots. Functionalization of these hydrogel with novel, brightly photoluminescent 2-amino-2-methyl-1-propanol quantum carbon dots (quantum yield of 62.5 %) results in a composite capable of specific interaction with hexavalent chromium. Quantitative fluorescence quenching measurements of the hydrogel composite in the presence of hexavalent chromium shows a limit of detection of 1.2 μM Cr6+ which is below maximum allowable concentrations for drinking water. The hydrogel composite is cheap to manufacture and can be injected into 96 well plates for high throughput analysis of environmental water samples. These results are encouraging for the development of hydrogels and polymetric films to be used as novel fluorescent sensing platforms for environmental diagnostic applications.Graphical abstractImage 1
       
  • Combining the advantages of multilevel and orthogonal partial least
           squares data analysis for longitudinal metabolomics: application to kidney
           transplantation
    • Abstract: Publication date: Available online 23 November 2019Source: Analytica Chimica ActaAuthor(s): Yoric Gagnebin, Julian Pezzatti, Pierre Lescuyer, Julien Boccard, Belen Ponte, Serge RudazKidney transplantation is one of the renal replacement options in patients suffering from end-stage renal disease (ESRD). After a transplant, patient follow-up is essential and is mostly based on immunosuppressive drug levels control, creatinine measurement and kidney biopsy in case of a rejection suspicion. The extensive analysis of metabolite levels offered by metabolomics might improve patient monitoring, help in the surveillance of the restoration of a “normal” renal function and possibly also predict rejection. The longitudinal follow-up of those patients with repeated measurements is useful to understand changes and decide whether an intervention is necessary.The time modality, therefore, constitutes a specific dimension in the data structure, requiring dedicated consideration for proper statistical analysis. The handling of specific data structures in metabolomics has received strong interest in recent years. In this work, we demonstrated the recently developed ANOVA multiblock OPLS (AMOPLS) to efficiently analyse longitudinal metabolomic data by considering the intrinsic experimental design. Indeed, AMOPLS combines the advantages of multilevel approaches and OPLS by separating between and within individual variations using dedicated predictive components, while removing most uncorrelated variations in the orthogonal component(s), thus facilitating interpretation. This modelling approach was applied to a clinical cohort study aiming to evaluate the impact of kidney transplantation over time on the plasma metabolic profile of graft patients and donor volunteers. A dataset of 266 plasma metabolites was identified using an LC-MS multi-platform analytical setup. Two separate AMOPLS models were computed: one for the recipient group and one for the donor group. The results highlighted the benefits of transplantation for recipients and the relatively low impacts on blood metabolites of donor volunteers.Graphical abstractImage 1
       
  • Rapid PCR-Free Meat Species Identification using Electric Field Induced
           Release and Measurement (EFIRM®)
    • Abstract: Publication date: Available online 23 November 2019Source: Analytica Chimica ActaAuthor(s): Michael Tu, Man Yee Wong, Xiaoxia Sun, Minxian Dai, Renping Huang, Ying Chen, Xiaoyan Lin, Qiuyue Zheng, Aifu Yang, Wei LiaoThis work details the usage of EFIRM® (Electric Field Induced Release and Measurement) for PCR-free rapid electrochemical detection of mitochondrial DNA. EFIRM® was able to perform highly sensitive detection of animal species for meat contamination testing without multistep sample lysis, DNA extraction, or PCR amplification steps, demonstrating the capability to detecti the presence of foreign meat species that only constituted 0.1% of the total mass of a food sample (achieving sensitivity equivalent to that of PCR). The EFIRM® strategy utilizes surface immobilized nucleic acid probes that complement to mitochondrial sequence of Ovis Aries, Sus Scrofa, and Bos Taurus and are immobilized in a polypyrrole matrix on a 96-electrode array. Quantification was performed through amperometric measurement of oxidation-reduction reactions on a streptavidin-peroxidase enzyme chain that completes the nucleic acid complex. All electrochemical procedures were performed using a high-throughput potentiostat system that allows parallelized electrochemical measurement and interfacing to the 96-electrode array.Graphical abstractImage 1
       
  • A new dicyanoisophorone-based ratiometric and colorimetric near-infrared
           fluorescent probe for specifically detecting hypochlorite and its
           bioimaging on a model of acute inflammation
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Jinshuai Lan, Jing Guo, Xiaoyi Jiang, Yi Chen, Zhenghao Hu, Yuanfang Que, Hongxin Li, Jingyi Gu, Rodney J.Y. Ho, Ruifeng Zeng, Yue Ding, Tong ZhangTo explore how hypochlorous acid (HClO) affects human health, a highly sensitive, selective, and trace detection method for hypochlorite (ClO−) is crucial for determining its non-negligible function in both environment and living systems. Herein, a dicyanoisophorone-phenylboronic acid-based novel ratiometric near-infrared fluorescent probe (Probe 1) was designed for the rapid and specific detection of ClO− based on the intramolecular charge transfer (ICT) mechanism. Excess addition of HClO to the Probe 1 solution, 186-times ratio (I652/I582) augment were gained. And this probe provided a colorimetric and ratiometric fluorescence response to ClO− with a high selectivity, a rapid response (within 30 s), and had an extremely low detection limit (15.7 nM). In addition, owing to the good sensing properties and low cytotoxicity of Probe 1, it can be used to expediently visualize exogenous ClO− in HepG2 cells and endogenous ClO− in RAW264.7 macrophage cells. Furthermore, the probe was successfully used for the bioimaging of zebrafish with an acute inflammation. Thus, Probe 1 is a promising vehicle to identify the level of HClO in animals with associated diseases.Graphical abstractA new ratiometric and colorimetric NIR fluorescent probe (Probe 1) for the specific detection of ClO− has been designed and synthesized on the basis of dicyanoisophorone-phenylboronic acid. And it was endowed with the following outstanding advantages: one-step synthesis, a long-wavelength emission, naked-eye assay, ratio fluorescent dual-channel detection, and feasibility in living cells and zebrafish.Image 1
       
  • Incorporation of homochiral metal-organic cage into ionic liquid based
           monolithic column for capillary electrochromatography
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Zhentao Li, Zhenkun Mao, Wei Zhou, Zilin ChenMetal-organic cages (MOCs) are a novel kind of porous materials which have three dimensional structures with perpetual and well-defined holes. They have attracted wide consideration for relatively simple synthesis and potential applications such as separation, sensing, microreactor and catalysis etc. In this study, a homochiral MOC [Zn3L2] was prepared as a novel stereoselective stationary phase and added into poly (ionic liquid-co-ethylene dimethacrylate) (Zn3L2@poly(IL-co-EDMA)) monolith for capillary electrochromatography (CEC). The chiral analytes comprising mandelic acid, benzoin and furoin enantiomer were separated perfectly using the monolithic column Zn3L2@poly(IL-co-EDMA), and the effects of buffer pH, acetonitrile percentage and buffer concentration on enantiomers separation were confirmed. Moreover, incorporation of MOC [Zn3L2] into IL polymer monolith strengthened obviously the stereoselective isolation of some positional isomers (such as nitrophenols, nitrotoluenes, xylenes, and ionones). The relative standard deviations (RSDs) of the retention time for intra-day (n = 5) and inter-day (n = 3) and column-to-column (n = 3) enantioseparations were all below 5.0%. This novel monolithic column combined distinct features of the stereoselective materials with the eminent traits of ionic liquid matrix, it has great application potential in CEC.Graphical abstractImage 1
       
  • Renewable magnetic ion-selective colorimetric microsensors based on
           surface modified polystyrene beads
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Sutasinee Apichai, Lu Wang, Kate Grudpan, Eric BakkerMagnetic ion-selective colorimetric microspheres based on surface modification of polystyrene beads (0.8 μm diameter) are reported for the first time. The common components of ion-selective optode sensing (chromoionophore, ion-exchanger and ionophore) and magnetic nanoparticles are adsorbed onto the surface of the polystyrene particles using a simple mixed solvent method. The average diameter of the magnetic microspheres is evaluated by dynamic light scattering as 0.79 ± 0.06 μm. The reversible microsensors are circulated by flow and accumulated at a single spot by an applied magnet to become observable by digital camera. Hue signals are extracted from the recorded images to quantify the ratio of protonated and deprotonated form of the chromoionophore, which is the basis for optode response. The resulting magnetic microsensors respond to K+ with excellent selectivity over the range of 10−6 M to 10−2 M and a response time of t99 
       
  • Controlled assembly of AIEgens based on a super-quadruplex scaffold for
           detection of plasma membrane proteins
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Longyi Zhu, Yang Li, Lei Zhang, Yunjie Wen, Huangxian Ju, Jianping LeiQuantification of plasma membrane proteins (PMPs) is crucial for understanding the fundamentals of cellular signaling systems and their related diseases. In this work, a super-quadruplex scaffold was designed to regulate assembly of oligonucleotide-grafted AIEgens for detection of PMPs. The nonfluorescence oligonucleotide-grafted AIEgen (Oligo-AIEgen) was firstly synthesized by attaching the AIEgen to 3′-terminus of the oligonucleotide through click chemistry. Meanwhile, the tetramolecular hairpin-conjugated super-quadruplex (THP-G4) as cleavage element and signal enhancement scaffold composited of three elements: a substrate sequence of DNAzyme in the loop region, partial hybridization region in the stem, and six guanine nucleotides to form G-quadruplex. Once the DNAzyme was anchored on the specific PMPs through aptamer-protein recognition, the substrate sequence on the loop of THP-G4 was cleaved by DNAzyme with the aid of cofactor MnII, resulting in the conformation switch of THP-G4 to the activated G-quadruplex scaffold. The latter could assemble Oligo-AIEgens to generate aggregation-induced emission (AIE) enhancement, resulting in a simple and sensitive strategy for detection of membrane proteins. Moreover, the DNAzyme continuously cut the next THP-G4 to achieve recycling amplification. Under the optimized conditions, this AIE-based strategy exhibited good linear relationship with the logarithm of MUC1 concentration from 0.01 to 10 μg mL−1 with the limit of detection down to 4.3 ng mL−1. The G4-assembled AIEgens provides a universal platform for detecting various biomolecules and a proof-of concept for AIE biosensing.Graphical abstractImage 1
       
  • A novel target and pH dual-activatable fluorescent probe for precisely
           detecting hypochlorite in lysosomes
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Lei Shi, Sheng Yang, Hao-Jia Hong, Yong Li, Hui-Juan Yu, Guang Shao, Kai Zhang, Sheng-Zhao GongHypochlorite (HClO) is involved in various physiological and pathological processes as well as regulation of lysosomal functions. Thus, it is appreciated to develop efficient molecule tools for precisely detecting HClO in lysosomes. Although several lysosomal-targetable fluorogenic probes for HClO have been developed to date, they still suffered from the discounted sensing performance under lysosomal acidic condition. Herein, on the basis of the “AND” logic gate strategy, a novel dual-activatable fluorogenic probe CS has been rationally designed by simultaneously incorporating HClO recognition site and pH-sensitive group with lysosomal-targetable characteristic into a coumarin fluorophore. Different from the single-activated ones previously reported, CS exhibited good sensitivity, high specificity and fast response towards HClO under the acidic conditions but was out of operation in the neutral or alkaline environment. Importantly, it had been successfully applied for spatial-resolution imaging of exogenous or endogenous HClO in lysosomes.Graphical abstractA novel dual-activatable fluorogenic probe CS has been rationally designed. This probe exhibited good sensitivity, high specificity and fast response towards HClO under the lysosomal acidic conditions, and it has been successfully applied for visualizing exogenous or endogenous HClO in lysosomes of living cells.Image 1
       
  • Near-infrared ratiometric probe with a self-immolative spacer for rapid
           and sensitive detection of alkaline phosphatase activity and imaging
           in vivo
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Xueyan Zhang, Xiangzhu Chen, Kaizheng Liu, Yuanyuan Zhang, Gui Gao, Xiaoqian Huang, Shicong HouAlkaline phosphatase (ALP), an enzyme that catalyzes the hydrolysis of phosphate groups, is closely associated with many diseases, including bone disease, prostate cancer, and diabetes. Thus, new assays for ALP detection in live cells are needed to better understand its role in related biological processes. In this study, we constructed a novel near-infrared ratiometric fluorescent probe for detecting ALP activity with high sensitivity. The probe uses a new self-immolative mechanism that can achieve a rapid response (within 10 min) to ALP, detected as a spectral shift (from 580 to 650 nm). This method effectively avoids issues related to instrument variability, and the near-infrared fluorescence emission (650 nm) makes it more suitable for biological detection. Moreover, the high sensitivity (14-fold enhancement of the fluorescence ratio F650/F580) and low detection limit (0.89 U L−1) for ALP allows the probe to be adapted to complex biological environments. The assay was successfully performed using serum samples with a linear range of ALP of up to 150 U L−1. We used the developed probe to detect and image endogenous ALP in cells with satisfactory results, and we successfully used the probes to detect changes in endogenous ALP levels in zebrafish caused by drug-induced organ damage.Graphical abstractImage 1
       
  • High sensitivity and non-background SERS detection of endogenous hydrogen
           sulfide in living cells using core-shell nanoparticles
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Wen-Shu Zhang, Ya-Ning Wang, Zhang-Run XuEndogenous hydrogen sulfide (H2S) exists in multiple physiological processes. In order to further understand the action mechanism of H2S in cells and human body, we proposed a smart surface-enhanced Raman scattering (SERS) nanoprobe, Au core-4-mercaptobenzonitrile-Ag shell nanoparticle (Au@4-MBN@Ag), for the detection of endogenous H2S in living cells based on the reaction between Ag shell and sulfide species. 4-MBN was selected as the SERS reporter to avoid interference from cellular molecules. With the sulfide concentration increasing, the Ag2S constantly formed, and consequently the SERS signal intensity of Au@4-MBN@Ag gradually decreased owing to the weaker SERS activity of Ag2S. With the nanoprobes, this method not only offers a high sensitivity for H2S detection at an nM level, but also achieves the goal of non-background analysis. It displays satisfactory anti-interference capability and a good linear relationship with sulfide concentration ranging from 50 nM to 500 μM, and an estimated detection limit is 0.14 nM. The Au@4-MBN@Ag nanoprobes were successfully applied to detect endogenous H2S in living HepG2 cells stimulated by pyridoxal 5-phosphate monohydrate. This work offers a potential analytical method in the related research of H2S physiological function.Graphical abstractImage 1
       
  • F-containing initiatior for ultrasensitive fluorescent detection of lung
           cancer DNA via atom transfer radical polymerization
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Jingyu Zhang, Qianrui Liu, Yanyan Ba, Jiamin Cheng, Huaixia Yang, Ying Cui, Jinming Kong, Xueji ZhangAn ultrasensitive fluorescence method for early diagnosis of lung cancer via Nafion-initiated atom transfer radical polymerization (ATRP) is reported, in this paper. In the proposed method, thiolated peptide nucleic acid (PNA) is modified to amino magnetic beads (MBs) via a cross-linking agent to specifically capture target DNA (tDNA), and the initiator (Nafion) of ATRP is attached to PNA/DNA heteroduplexes based on the phosphate groups of the tDNA and sulfonate groups of Nafion via phosphate-Zr4+-sulfonate chemistry. Nafion as a macroinitiator of ATRP possesses multiple C–F active sites to initiate polymerization, and numerous polymeric chains that significantly amplify the fluorescent signal are formed. Under optimal conditions, a good linear relationship is obtained in the range of 0.1 nM–0.1 fM with correlation coefficients of 0.9975, and the detection limit is as low as 35.5 aM (∼214 molecules). The proposed strategy has several advantages of simplicity, cost-effectiveness, selectivity and sensitivity. More importantly, the anti-interference results demonstrate that the proposed Nafion-initiated ATRP strategy has great potential in bioanalytical applications.Graphical abstractAn ultrasensitive fluorescence method for early diagnosis of lung cancer via Nafion-initiated atom transfer radical polymerization (ATRP) was reported.Image 1
       
  • Comparison of three sample addition methods in competitive and sandwich
           colloidal gold immunochromatographic assay
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Yu Li, Yaofeng Zhou, Xirui Chen, Xiaolin Huang, Yonghua XiongImmunochromatographic assays (ICAs) are mainstream point-of-care diagnostic tools in disease control, food safety, and environmental monitoring. However, the important issue pertaining to the influence of sample addition methods on the detection performance of ICAs has not been addressed, and related information is still lacking. Herein, we selected the well-accepted gold nanoparticles (AuNPs) as visual labels. AuNP-based ICA was then used to explore the effects of three sample addition methods (i.e., dry, wet, and insert) on the analytical performance of ICAs by using competitive and sandwich models. Under optimized conditions, the competitive ICA with clenbuterol as an analyte showed a negligible difference (p > 0.05) in the detection performance of the three methods in ideal phosphate buffered saline solution. However, the wet method demonstrated the worst performance in pork samples (p 
       
  • A sensitive and selective electrochemical sensor based on N, P-Doped
           molybdenum Carbide@Carbon/Prussian blue/graphite felt composite electrode
           for the detection of dopamine
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Sen Yang, Jihua Zhao, Simon Tricard, Laxian Yu, Jian FangIn this paper, a composite electrode of N,P-doped Mo2C@C/Prussian blue (PB)/graphite felt (N,P–Mo2C@C/PB/GF) was prepared by a simple method and used for sensitive and effective detection of dopamine (DA). N,P-doped Mo2C nanospheres were prepared by using phosphomolybdic acid (PMo12) as an initiator to promote the polymerization of polypyrrole. Such nanospheres were used to accelerate the deposition process of PB from K3[Fe(CN)6] and FeCl3 in solution. The N,P–Mo2C@C/PB nanohybrid was then anchored to GF in order to obtain the electrochemical sensor. Two linear ranges were extrapolated for dopamine detection: from 0.18 to 30 μmol L−1 with a sensitivity of 0.268 μA μmol−1, and from 30 to 280 μmol L−1 with a sensitivity of 0.045 μA μmol−1. The device showed a detection limit as low as 0.011 μmol L−1, an excellent selectivity to DA over common interfering analytes, and a favorable long-time stability. Finally, the sensor was used for quantitative analysis of DA in the 10-fold dilution of human serum (10%) and exhibited a satisfactory recovery.Graphical abstractImage 1
       
  • Gold-nanourchin seeded single-walled carbon nanotube on voltammetry sensor
           for diagnosing neurogenerative Parkinson’s disease
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Rui Zhang, Shan Wang, Xiaoming Huang, Yihang Yang, Haitao Fan, Fan Yang, Jie Li, Xushuai Dong, Shaobin Feng, Periasamy Anbu, Subash C.B. Gopinath, Tao Xinα-synuclein is a predominantly expressing neuronal protein for understanding the neurodegenerative disorders. A diagnosing system with aggregated α-synuclein encoded by SNCA gene is necessary to make the precautionary treatment against Parkinson’s disease (PD). Herein, gold-nanourchin conjugated anti-α-synuclein antibody was desired as the probe and seeded on single-walled carbon nanotube (SWCN) integrated interdigitated electrode (IDE). The surface morphology of SWCN-modified IDE and gold urchin-antibody conjugates were observed under FESEM, FETEM and AFM, the existing elements were confirmed. Voltammetry analysis revealed that the limit of fibril-formed α-synuclein detection was improved by 1000 folds (1 fM) with gold-nanourchin-antibody modified surface, compared to the surface with only antibody (1 pM). Validating the interaction of α-synuclein by Enzyme-linked Immunosorbent Assay was displayed the detection limit as 10 pM. IDE has a good reproducibility and a higher selectivity on α-synuclein as evidenced by the interactive analysis with the control proteins, PARK1 and DJ-1.Graphical abstractImage 1
       
  • Simultaneous targeted and untargeted UHPLC-ESI-MS/MS method with
           data-independent acquisition for quantification and profiling of
           (oxidized) fatty acids released upon platelet activation by thrombin
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Malgorzata Cebo, Jörg Schlotterbeck, Meinrad Gawaz, Madhumita Chatterjee, Michael LämmerhoferIn this study, a combined targeted/untargeted UHPLC-ESI-QTOF-MS/MS method for the targeted quantitative analysis of the primary platelet lipid mediators thromboxane B2 (TXB2), 12S-hydroxy-5Z,8E,10E-heptadecatrienoic acid (HHT) and its oxidation product 12-keto-5Z,8E,10E-heptadecatrienoic acid (KHT) was developed, which allowed simultaneous untargeted profiling for the detection of other lipid biomarkers such as other oxylipins and fatty acids (FAs) in platelet releasates. A general procedure for the synthesis of keto-analogs from hydroxylated polyunsaturated FAs (PUFAs) using Dess-Martin periodinane oxidation reagent was proposed for the preparation of KHT standard. MS detection was performed in data independent acquisition (DIA) mode with sequential window acquisition of all theoretical fragment ion mass spectra (SWATH) in the range of 50–500 Da with variable window sizes. The LC-MS/MS assay was validated for the targeted analytes and applied for analysis of supernatants derived from resting platelets and from platelets treated with thrombin. The targeted analytes KHT, HHT and TXB2 were found at highly elevated levels in the activated platelet releasates. On average, 13 ± 7, 15 ± 9, and 0.6 ± 0.2 attomols per platelet were released upon thrombin-activation. Furthermore, the simultaneous untargeted profiling (n = 8 in each group) revealed that these oxylipins are released with a pool of other (significantly upregulated) oxidized (12-HETE, 12-HEPE) and non-oxidized PUFAs. All these compounds can be considered additional biomarkers of platelet activation complementing the primary platelet activation marker thromboxane B2. The other lipids may support platelet activation or trigger other biological actions with some potential implications in thromboinflammation.Graphical abstractImage 1
       
  • Polymeric ionic liquid immobilized onto paper as sorptive phase in
           microextraction
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Julia Ríos-Gómez, María Teresa García-Valverde, Ángela Inmaculada López-Lorente, Carla Toledo-Neira, Rafael Lucena, Soledad CárdenasA new planar sorptive phase based on the simple immobilization of polymeric ionic liquids on paper is proposed. The sorptive phase can develop hydrophobic or mixed-mode (combining hydrophobic and ion exchange) interactions with the target analytes. The polymer is prepared by the Radziszewski reaction, which takes place in aqueous media, and it has been thoroughly characterized by different techniques including infrared spectroscopy, matrix-assisted laser desorption/ionization coupled to high-resolution mass spectrometry and proton nuclear magnetic resonance. Three different strategies aimed to immobilize the polymeric ionic liquid on paper have been evaluated. Among them, simple thermal curing at 120 °C was selected. The as-prepared paper has been evaluated for the extraction of several non-steroidal anti-inflammatory drugs from urine, the analytes being finally determined by liquid chromatography with tandem mass spectrometry. The method detection limits were 3.8, 7.2, 6.8, 9.4, 15.7, and 5.1 μg/L for indomethacin, diclofenac, tolmetin, ketoprofen, naproxen, and ibuprofen, respectively. Calibration models were linear (R2 > 0.9949) up to 1000 μg/L. The intra-day precision, expressed as relative standard deviation and calculated at three different concentrations levels (limit of quantification, 250 μg/L, and 1000 μg/L), varied between 1.1 and 13%. The accuracy, calculated as relative recovery, was in the range from 72 to 95%, thus being considered appropriate. The easiness of polymeric ionic liquid paper synthesis and the multi-sample extraction protocol designed allows the processing of a high number of samples at the same time.Graphical abstractImage 1
       
  • Total polyphenol content and metals determination in Spanish virgin olive
           oils by means of a dispersive liquid-liquid aerosol phase extraction
           method and ICP-MS
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Carolina Mirón, Raquel Sánchez, Soledad Prats, José-Luis TodolíThis report presents a study on the determination of total polyphenols together with metals in several samples of olive oil produced in Spain. The results provided by applying a conventional extraction method were compared against those encountered by means of the so-called Dispersive Liquid-Liquid Aerosol Phase Extraction method. The novel method is based on the dispersion of the extracting solution in the sample. To accomplish this, an aerosol is pneumatically generated and directed against the surface of the oil sample. The aerosol was generated in order to increase as much as possible the surface area of the interface between the two involved non-miscible phases. As a result, the partition equilibrium was quickly achieved. The critical variables dictating the characteristics of the obtained aerosols as well as those influencing the partition equilibrium state were studied. With the aerosol phase extraction method, the values corresponding to the total polyphenols and metals in real samples were not statistically different as compared to those obtained by the conventional liquid – liquid extraction method. The new method provided shorter extraction times and lower mass of consumed reagents than the conventional one, thus giving rise to a more environmentally friendly method. For polyphenols, calculated limits of detection and quantification were 0.48 and 1.5 mg of gallic acid kg−1, respectively. The absorbance linearity, in turn, was kept from 0 to 50 mg kg−1 (R2 = 0.998). In the case of metal and metalloid quantification, the limits of detection found with a sample digestion method ranged from 1.3 (Cu) to 291 (Na) ng mL−1. Meanwhile, because of the lower dilution factor, this parameter was one order of magnitude lower when these elements were extracted according to the new method. The new extraction method was applied to the analysis of 42 extra virgin olive oils both bottled and directly collected from the oil press, containing single cultivars or blends and produced from different areas. Fresh oils were analyzed and a preliminary study on the oil thermal degradation was also done. Dispersing the extracting solution as an aerosol into the sample can be considered a versatile method able to provide extensive oil chemical information in a rapid way what is especially important in the case of polyphenols.Graphical abstractA dispersive liquid – liquid aerosol phase extraction method has been applied optimized and validated for the determination of polyphenols and metals in extra virgin olive oils.Image 1
       
  • Stable Pb2+ ion-selective electrodes based on
           polyaniline-TiO2 solid contacts
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Xianghua Zeng, Wenen Jiang, Xiaohui Jiang, Geoffrey I.N. Waterhouse, Zhiming Zhang, Liangmin YuA novel Pb2+ ion selective electrode based on a polyaniline-doped titanium dioxide (PANI-TiO2) solid contact, denoted herein as GC/PANI-TiO2/Pb2+-ISE, was successfully developed. The GC/PANI-TiO2/Pb2+-ISE exhibited a stable and rapid potential response to Pb2+ ions, with a linear response over the concentration range 10−3-10−9 M, a detection limit of ∼10−9.1 M and a response time of only 10–15 s. The PANI-TiO2 solid contact layer possessed a large specific capacitance, thereby effectively promoting ion-to-electron transduction and enhancing the output stability (potential drift, 122.6 μV/s). The developed electrode maintained excellent performance during continuous use, showing a linear response range of 10−3-10−7 M with no obvious changes in the potential response time or response slope (29 ± 0.2 mV/decade) over six weeks. Results encourage the wider use of conducting polymer-semiconductor solid contacts in ion selective electrode development.Graphical abstractImage 1
       
  • Competitive electrochemical aptasensor based on a cDNA-ferrocene/MXene
           probe for detection of breast cancer marker Mucin1
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Haiyan Wang, Jingjing Sun, Lin Lu, Xiao Yang, Jianfei Xia, Feifei Zhang, Zonghua WangA competitive electrochemical aptasensor based on a cDNA-ferrocene/MXene probe is used to detect the breast cancer marker Mucin1 (MUC1). MXene (Ti3C2) nanosheets with excellent electrical conductivity and large specific surface area are selected as carriers for aptamer probes. The ferrocene-labeled complementary DNA (cDNA-Fc) is first bound on the surface of MXene to form a cDNA-Fc/MXene probe. Then, the MUC1 aptamer is fixed to the electrode by Au–S bonds. The sensing electrode is named Apt/Au/GCE. After the probe is complementary to the aptamer, a cDNA-Fc/MXene/Apt/Au/GCE aptasensor is fabricated. When the aptasensor is used for detection of MUC1, a competitive process happens between the cDNA-ferrocene/MXene probe and MUC1, which makes cDNA-Fc/MXene probe detach from the sensing electrode, resulting in a decrease in electrical signal. The difference in the corresponding peak current before and after the competition can be used to indicate the quantitative change in bound MUC1. The proposed competitive electrochemical aptasensor gives a wide linear range of 1.0 pM–10 μM and a low detection limit of 0.33 pM (S/N = 3), which is promising for clinical diagnosis.Graphical abstractImage 1
       
  • HPLC-ICPMS/MS shows a significant advantage over HPLC-ICPMS for the
           determination of perchlorate in ground, tap, and river water
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Bassam Lajin, Walter GoesslerPerchlorate is an environmental contaminant that originates from anthropogenic as well as natural sources. The health effects of perchlorate with respect to the thyroid function are well known. The capabilities of the inductively coupled plasma mass spectrometry (ICPMS) has been recently expanded by coupling with tandem mass spectrometry. The advantages of HPLC-ICPMS/MS has not yet been thoroughly assessed for chlorine speciation analysis. We report a rapid and simple method for perchlorate determination in ground, tap, and river water and we show that the ICPMS/MS offers as a chromatographic detector at least 10-fold improvement in the detection limit relative to single quadrupole ICPMS. The achieved limit of detection was 0.3 μg Cl L−1 perchlorate and could be yet improved by simple freeze-drying (down to ca. 50 ng Cl L−1, based on the river water matrix), which is comparable with HPLC-ESIMS/MS, with the advantage of eliminating the need for the 18O-perchlorate isotopically labeled internal standard. The method was validated in the various water matrices in terms of recovery at levels 5.0–250 μg Cl L−1 (±10%), repeatability (RSD
       
  • Selective hybridization and capture of KRAS DNA from plasma and blood
           
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Miranda N. Emaus, Chenghui Zhu, Jared L. AndersonDetection of circulating tumor DNA (ctDNA) presents several challenges due to single-nucleotide polymorphisms and large amounts of background DNA. Previously, we reported a sequence-specific DNA extraction procedure utilizing functionalized oligonucleotides called ion-tagged oligonucleotides (ITOs) and disubstituted ion-tagged oligonucleotides (DTOs). ITOs and DTOs are capable of hybridizing to complementary DNA for subsequent capture by a magnetic ionic liquid (MIL) through hydrophobic interactions, π-π stacking, and fluorophilic interactions. However, the performance of the ITOs and DTOs in complex sample matrices has not yet been evaluated. In this study, we compare the amount of KRAS DNA extracted using ITO and DTOs from saline, 2-fold diluted plasma, 10-fold diluted plasma, and 10-fold diluted blood. We demonstrate that ITO/DTO-MIL extraction is capable of selectively preconcentrating DNA from diluted plasma and blood without additional sample preparation steps. In comparison, streptavidin-coated magnetic beads were unable to selectively extract DNA from 10-fold diluted plasma and 10-fold diluted blood without additional sample clean-up steps. Significantly more DNA could be extracted from 2-fold diluted plasma and 10-fold diluted blood matrices using the DTO probes compared to the ITO probes, likely due to stronger interactions between the probe and MIL. The ability of the DTO-MIL method to selectively preconcentrate small concentrations of DNA from complex biological matrices suggests that this method could be beneficial for ctDNA analysis.Graphical abstractImage 1
       
  • Outside Front Cover
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s):
       
  • Low field nuclear magnetic sensing technology based on hydrogel-coated
           superparamagnetic particles
    • Abstract: Publication date: 15 January 2020Source: Analytica Chimica Acta, Volume 1094Author(s): Qi-Yue Guo, Shu-Yue Ren, Jing-Yi Wang, Ye Li, Zi-Yi Yao, Hui Huang, Zhi-Xian Gao, Shi-Ping YangBased on superparamagnetic nanoparticles, a responsive polyacrylamide hydrogel self-assembled by nucleic acid hairpin hybridization chain reaction was designed, and a universal low field nuclear magnetic resonance sensing platform was successfully constructed. As the target was gradually added, the hydrogel coating on the surface of the magnetic nanoparticle was opened layer by layer through binding with the aptamer, which specifically bonded thereto, causing different degrees of exposure of the magnetic nanoparticle, resulting in changes of low field nuclear magnetic resonance signals. This method was originally applied to the rapid detection of adenosine triphosphate (ATP), and the versatility of the method was verified using polychlorinated biphenyl 77 (PCB77). This method had the advantage of being fast, convenient, and low cost, and it can be easily operated with high repeatability. This universal method can detect a variety of targets by replacing aptamers and may be useful in controlling food quality and for rapidly detecting cancer cells in vitro.Graphical abstractImage 1
       
  • Immobilization of porcine pancreatic lipase onto a metal-organic
           framework, PPL@MOF: A new platform for efficient ligand discovery from
           natural herbs
    • Abstract: Publication date: Available online 22 November 2019Source: Analytica Chimica ActaAuthor(s): Xinlin Chen, Shang Xue, Yaolan Lin, Jianguang Luo, Lingyi KongIn terms of ligand fishing, the amount and the relative activity recovery of enzymes immobilized on magnetic particles and nanoparticles are not preeminent. Therefore, the metal-organic framework (MOF) UiO-66-NH2 was synthesized to immobilize the porcine pancreatic lipase (PPL) via precipitation-cross-linking, and the resulting novel biological matrices named PPL@MOF manifested high PPL loading capacity (98.31 mg) and relative activity recovery (104.4%). Moreover, the novel enzyme-MOF composite was applied to screen lipase inhibitors from Prunella vulgaris L. to enrich and improve the techniques of ligand fishing. As a result, 13 lipase ligands were obtained, and 12 compounds were determined by HPLC-Q-TOF-MS/MS. All of these ligands were further confirmed to be potential inhibitors through the verification of the activity assay and molecular docking. The proposed approach based on PPL@MOF was superior in terms of abundant protein loading capacity, high enzyme catalytic activity and easy preparation process. Taken together, our newly developed method provided a new platform for efficient discovering bioactive molecules from natural herbs.Graphical abstractImage 1
       
  • A Review on Recent Advances in the Applications of Surface-Enhanced Raman
           Scattering in Analytical Chemistry
    • Abstract: Publication date: Available online 22 November 2019Source: Analytica Chimica ActaAuthor(s): Meikun Fan, Gustavo F.S. Andrade, Alexandre G. BroloThis review is focused on recent developments of surface-enhanced Raman scattering (SERS) applications in Analytical Chemistry. The work covers advances in the fabrication methods of SERS substrates, including nanoparticles immobilization techniques and advanced nanopatterning with metallic features. Recent insights in quantitative and sampling methods for SERS implementation and the development of new SERS-based approaches for both qualitative and quantitative analysis are discussed. The advent of methods for pre-concentration and new approaches for single-molecule SERS quantification, such as the digital SERS procedure, has provided additional improvements in the analytical figures-of-merit for analysis and assays based on SERS. The use of metal nanostructures as SERS detection elements integrated in devices, such as microfluidic systems and optical fibers, provided new tools for SERS applications that expand beyond the laboratory environment, bringing new opportunities for real-time field tests and process monitoring based on SERS. Finally, selected examples of SERS applications in analytical and bioanalytical chemistry are discussed.The breadth of this work reflects the vast diversity of subjects and approaches that are inherent to the SERS field. The state of the field indicates the potential for a variety of new SERS-based methods and technologies that can be routinely applied in analytical laboratories.Graphical abstractImage 1
       
  • Synergistic effect of the combination therapy on ovarian cancer cells
           under microfluidic conditions
    • Abstract: Publication date: Available online 22 November 2019Source: Analytica Chimica ActaAuthor(s): Magdalena Flont, Elżbieta Jastrzębska, Zbigniew BrzózkaOvarian cancer belongs to the group of gynecological cancers and indicates the high resistance to many drugs used in standard anticancer therapy. The treatment of ovarian cancer is a big challenge for the present medicine. In our report we tested the effectiveness of the combination anticancer therapy against ovarian cells: human ovarian carcinoma (A2780) and human ovarian fibroblasts (HOF). Two different types of drugs were used: doxorubicin (DOX) and a new-generation photosensitizer, nanoencapsulated meso-tetraphenylporphyrin (nano-TPP). The aim of the research was to compare the effect of the sequential combination therapy (chemotherapy with DOX and photodynamic therapy with nano-TPP) carried out in static and dynamic conditions. To achieve dynamic culture conditions, similar to in vivo environment, we designed a new microfluidic system in which the simultaneous, independent cultures of two cell lines (non-malignant and cancer cells) and their one-step analysis were possible. We observed that the sequential combination of photodynamic therapy (PDT) with chemotherapy allowed to obtain the synergistic effect of the treatment with using low doses of drugs. We also confirmed that the use of microfluidic conditions significantly increased the effectiveness of combination therapy and allowed for maintaining a high selectivity of the action of drugs on cancer cells. To the best of our knowledge, for the first time the microfluidic system was used to carry out sequential combination therapy against ovarian cancer.Graphical abstractImage 1
       
  • Online Sample Clean-up and Enrichment of Proteins from Salty Media with
           Dynamic Double Gradients on a Paper Fluidic Channel
    • Abstract: Publication date: Available online 22 November 2019Source: Analytica Chimica ActaAuthor(s): Yu Cai, Ji-Cheng Niu, Yu-Qi Liu, Xin-Li Du, Zhi-Yong WuPaper-based analytical device (PAD) has received more and more attention in the field of point-of-care test (POCT) due to its low cost, portability and simple operation. Sensitivity and selectivity are two important aspects in clinical diagnostic analysis. However, low sensitivity of a PAD limits its wider application for POCT. Here we introduced a PAD that can clean and enrich the protein content from salty media with both electric field (E) and pH gradient (double E/pH gradients), with which 100-fold enrichment effect could be achieved within 70 s as demonstrated by fluorescein isothiocyanate labeled bovine serum albumin (FITC-BSA) from artificial urine media. With post staining of the protein stacking band with bromophenol blue (BPB), selective colorimetric detection of human serum albumin (HSA) was achieved simply with smartphone camera in the clinically significant range of 10∼300 mg‧L-1 (R2=0.99) with a limit of detection (LOD) of 4.9 mg‧L-1. Detection of microalbuminuria (MAU) of diabetic patients was demonstrated with this method without difference (ɑ=0.01) to that by the clinical method (immunoturbidimetry). This work demonstrated the potential of this PAD method in online sample pretreatment and detection of target component from complex physiological samples.Graphical abstractImage 1
       
  • Sensitive and selective SERS probe for detecting the activity of
           γ-glutamyl transpeptidase in serum
    • Abstract: Publication date: Available online 21 November 2019Source: Analytica Chimica ActaAuthor(s): Lei Jiang, Dan Guo, Lu Wang, Shuai Chang, Jia-Bin Li, De-Sheng Zhan, Essy Kouadio Fodjo, Hai-Xin Gu, Da-Wei Liγ-Glutamyl transpeptidase (GGT) has attracted considerable attention for its regulatory effect on glutathione metabolism in living organisms; further, its close relationship with physiological dysfunctions such as hepatitis and liver cancers has enhanced its applicability. Therefore, the accurate detection of GGT levels is particularly important for the early diagnosis of diseases. Thus, we herein report the development of a surface-enhanced Raman spectroscopic (SERS) probe, namely bis-s,sʹ-((s)-4,4ʹ-thiolphenylamide-Glu) (b-(s)-TPA-Glu), that comprises of a γ-glutamyl moiety for detection of the GGT activity. In this system, detection was achieved by observing differences in the SERS spectral profiles of the b-(s)-TPA-Glu probe and its corresponding hydrolysis product that resulted from the catalytic action of GGT. This SERS probe system exhibited a high selectivity toward GGT due to a combination of its specific catalytic action and the distinctive spectroscopic fingerprint of the SERS technique. The developed SERS approach was also found to be approximately linear in the range of 0.2 to 200 U/L, and a limit of detection of 0.09 U/L was determined. Furthermore, the proposed SERS method was suitable for detection of the GGT activity of clinical serum samples and also for evaluation of the inhibitors of GGT. Consequently, this approach is considered to be a promising diagnostic and drug screening tool for GGT-associated diseases.Graphical abstractImage 1
       
  • Toxic and Potentially Toxic Elements Determination in Cosmetics Used for
           Make-up: A Critical Review
    • Abstract: Publication date: Available online 21 November 2019Source: Analytica Chimica ActaAuthor(s): Marcia Foster Mesko, Diogo La Rosa Novo, Vanize Caldeira da Costa, Alessandra Schneider Henn, Erico Marlon Moraes FloresThe daily use of cosmetics may expose consumers to localized skin problems and systemic effects caused by absorption of chemical elements. The requirements for suitable quality control and maximum limits for toxic and potentially toxic elements in cosmetics have attracted the attention of the scientific community and official institutions around the world. Maximum limits for chemical elements in some cosmetics have been set, but there are disagreements between them. In the same context, many analytical methods have been proposed in the literature, but several challenges during the sample preparation and determination steps related to the high complexity of cosmetics’ matrices composition still remain. It is extremely difficulty to establish suitable methods, free of interference, even using modern technology. In this review, methods for determining toxic and potentially toxic elements in cosmetics used for make-up on the lips and the eye area, covering the period since 2000, are presented. Techniques enabling direct analysis and those requiring a sample preparation step prior to the analysis are also discussed. This review focused on cosmetics for make-up on the lips and the eye area because the risks of percutaneous absorption and oral ingestion of toxic and potentially toxic elements is higher than in other body regions.Graphical abstractImage 1
       
  • Polymerization nicking-triggered LAMP cascades enable exceptional signal
           amplification for aptamer-based label-free detection of trace proteins in
           human serum
    • Abstract: Publication date: Available online 20 November 2019Source: Analytica Chimica ActaAuthor(s): Tingting Zhang, Lin Xu, Bingying Jiang, Ruo Yuan, Yun XiangDetecting molecular biomarkers in high sensitivity plays an important role in the diagnosis of various diseases at the early stage. Here, by combining the target-induced polymerization nicking reaction (TIPNR) with the loop-mediated isothermal amplification (LAMP), we describe an ultrasensitive and label-free aptamer-based sensing method for detecting low levels of proteins in human serum by using thrombin as the model target analyte. The target thrombin binds and causes spontaneous assembly of two distinct aptamer probes to form the templates for the polymerization nicking reaction recycling amplification to produce many forward inner primer sequences. Subsequently, downstream LAMP reactions are initiated by these sequences for the generation of tremendous DNA hairpins with various lengths via automated cyclic strand displacement reactions. The SYBR Green I organic dye further binds the many hairpins to show drastically amplified fluorescence for ultrasensitive detection of thrombin down to 3.6 fM in the linear range from 0.01 pM to 10 nM. Such a sensing method based on aptamers has high discrimination capability for the target molecules against other non-specific proteins and is applicable for diluted serum samples. With the successful demonstration of the substantial signal amplification ability and simplicity feature of this assay approach, highly sensitive and convenient detection of other disease biomarkers with this method can be envisioned in the near future.Graphical abstractImage 1
       
  • Improved Validation for Single Particle ICP-MS Analysis Using a Pneumatic
           Nebulizer / Microdroplet Generator Sample Introduction System for
           Multi-mode Nanoparticle Determination
    • Abstract: Publication date: Available online 20 November 2019Source: Analytica Chimica ActaAuthor(s): Daniel Rosenkranz, Fabian L. Kriegel, Emmanouil Mavrakis, Spiros A. Pergantis, Philipp Reichardt, Jutta Tentschert, Norbert Jakubowski, Peter Laux, Ulrich Panne, Andreas LuchThis study reports on the development of a single-particle (sp) inductively coupled plasma mass spectrometry (ICP-MS) technique suitable for the multi-mode determination of nanoparticle (NP) metal mass fraction and number concentration. The described technique, which is based on a dual inlet system consisting of a pneumatic nebulizer (PN) and a microdroplet generator (MDG), allows for the sequential introduction of ionic metal calibrant solutions and nanoparticle suspensions via all combinations of the two inlets; thus allowing for a combination of three independent modes of analysis. A novel interface, assembled using standard analytical components (a demountable quartz ICP-MS torch, flexible non-conducting silicon tubing and various connectors), was used to interface the dual inlet system to an ICP-MS. The interface provided improved functionality, compared to a previous design. It is now possible to conveniently exchange and introduce standard solutions and samples via all inlet combinations, analyze them, and also wash the sample inlet systems while the whole setup is still connected to an operating ICP-MS. This setup provided seamless and robust operation in a total of three analysis modes, i.e. three ways to independently determine the metal mass fraction and NP number concentration. All three analyses modes could be carried out within a single analytical run lasting approximately 20 minutes. The unique feature of the described approach is that each analysis mode is based on a different calibration principle, thus constituting an independent way to determine metal mass fractions and nanoparticle number concentrations. Conducting the three independent state-of-the-art analysis, within a single analytical run, improves substantially the validation capabilities of sp-ICP-MS for NP analysis. To assess the technique’s analytical performance, Au, Ag and CeO2 nanoparticles were analyzed. The determined average diameters for Au (56.7 ± 1.5 nm), Ag (72.8 ± 3.4 nm) and CeO2 (69.0 ± 6.4 nm) NPs were in close agreement for all three modes of analysis, as well as with the values provided by suppliers’ for Au and Ag NPs (56.0 ± 0.5 for Au, 74.6 ± 3.8 nm for Ag). However, the determined average value for CeO2 was much higher than the expected 28.4 ± 10.4 nm, possibly due to NP agglomeration and the inability to detect NPs existing within the lower size range. The determined NP number concentrations, using analysis modes –I and -II, gave recoveries between 91-100% for the Au and Ag NP number concentrations. Whereas analysis mode –III showed a recovery of 70-88% for the same materials. Because of the polydispersity, the small size and polyhedral shape of the CeO2 NPs it was not possible to make NP number concentration comparisons for this material.Graphical abstractImage 1
       
  • Application of graphene/zinc-based metal-organic framework nanocomposite
           for electrochemical sensing of As(III) in water resources
    • Abstract: Publication date: Available online 20 November 2019Source: Analytica Chimica ActaAuthor(s): Mehdi Baghayeri, Masoud Ghanei-Motlagh, Reza Tayebee, Maryam Fayazi, Fatemeh NarenjiIn this study, a novel nanocomposite of graphene oxide/zinc based metal-organic framework (GO/MOF) was prepared through a simple solvothermal method. The electrochemical As(III) sensing capability of the nanocomposite was explored by casting the GO/MOF on a glassy carbon electrode (GCE), followed by an electrochemically reduction of GO. As(III) detection was performed by the differential pulse anodic stripping voltammetry (DPASV) method after closed-circuit mode. The present sensor showed excellent electrochemical performance such as a wide linear range from 0.2 to 25 ppb (μg/L), low detection limit (S/N=3) of 0.06 ppb and good reproducibility with a relative standard deviation (RSD) value of 2.1%. The detection limit of As(III) is lower than the threshold value set by the Environmental Protection Agency (EPA) in drinking water. A good selectivity for As(III) detection by the proposed Gr/MOF-GCE was also demonstrated. Finally, this platform was employed for the As(III) monitoring in environmental water samples, and the accuracy of obtained results were confirmed by inductively coupled plasma-optical emission spectrometer (ICP-OES) system.Graphical abstractImage 1
       
  • Amino bearing core-shell structured magnetic covalent organic framework
           nanospheres: Preparation, postsynthetic modification with phenylboronic
           acid and enrichment of monoamine neurotransmitters in human urine
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Yanping Wang, Shaoping Wu, Dan Wu, Jiwei Shen, Yinmao Wei, Chaozhan WangCovalent organic frameworks (COFs) have been increasingly employed in separation science, including sample preparation. Herein we fabricated the amino bearing core-shell structured COFs nanospheres [Fe3O4@TpBD(NH2)2], and a novel magnetic boronate affinity adsorbent was synthesized by postsynthetic modification of the Fe3O4@TpBD(NH2)2 with 2-formylphenylboronic acid. The magnetic boronate affinity adsorbent possesses fast magnetic response and high binding capacity up to 1037 μmol g−1 for dopamine. Besides, it was used as an adsorbent for extraction of urinary monoamine neurotransmitters at neutral pH. A method for detection of the monoamine neurotransmitters was developed by coupling the magnetic solid phase extraction with high-performance liquid chromatography-fluorescence detection. Under the optimized conditions, a good analytical method was obtained in the linear dynamic range of 2–200 ng mL−1 with R2 between 0.9917 and 0.9966, with low limit of detection (0.31–0.54 ng mL−1) and limit of quantification (1.04–1.80 ng mL−1). The recoveries of the monoamine neurotransmitters were in the range of 86.3–115%, with relative standard deviations of 2.34–10.5% (intra-day) and 2.84–14.4% (inter-day). The method was successfully applied to the determination of the monoamine neurotransmitters in human urine samples. This work is of great importance for preparing functionalized core-shell structured magnetic covalent organic framework nanospheres, it also demonstrates the feasibility of the functionalized magnetic COFs as adsorbents in sample pretreatment.Graphical abstractImage 1
       
  • Mixed-mode chromatography characteristics of chiralpak ZWIX(+) and
           ZWIX(−) and elucidation of their chromatographic orthogonality for
           LC × LC application
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Stefanie Bäurer, Martina Ferri, Andrea Carotti, Stefan Neubauer, Roccaldo Sardella, Michael LämmerhoferTwo-dimensional liquid chromatography requires orthogonal columns and/or separation principles in the first and second separation dimension. It is sometimes not straightforward to achieve. Chiral columns could expand the toolbox for 2D-LC, but are rarely exploited for this purpose, not least due to missing understanding of retention principles under non-chiral application conditions. To gain more insight, in this study Chiralpak ZWIX(+) and ZWIX(−), based on zwitterionic quinine and quinidine carbamate selectors, were carefully characterized by molecular dynamics simulations, lipophilicity/hydrophilicity measurements of selectors, pH-dependent ζ-potential determinations, and chromatographic characterization in RPLC and HILIC modes combined with unsupervised principal component analysis to extract classification of these columns in comparison to a number of commercial benchmarks (RP, HILIC and mixed-mode columns). The results showed that these chiral columns can be classified as mixed-mode chromatography phases with balanced lipophilic-hydrophilic surface character, excess of negative net charge due to sulfonic acid groups (in spite of weakly basic quinuclidine and quinoline rings), and multimodal applicability (RP, HILIC and polar organic elution modes). Orthogonality mapping in comparison to a number of modern HILIC and mixed-mode columns revealed that Poroshell HILIC-Z (with a zwitterionic ligand on 2.7 μm core-shell particles) can be beneficially combined as second dimension with the ZWIX column for comprehensive LC × LC. The online hyphenation of this 2D-LC system with complementary detection modalities including UV (DAD for chromophoric substances), charged aerosol detection (for universal detection and calibration of non-volatile analytes) and high-resolution mass spectrometry (ESI-QTOF-MS/MS for identification) provided an advanced method for comprehensive impurity profiling, applicable for instance for amino acid pharmaceutical products.Graphical abstractImage 1
       
  • Highly sensitive α-amanitin sensor based on molecularly imprinted
           photonic crystals
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Xiuzhen Qiu, Weimao Chen, Yiling Luo, Yulin Wang, Yanlian Wang, Huishi Guoα-amanitin is the most toxic amanita in mushrooms with lethal dose to humans around 0.1 mg. Kg−1. Hence, early identification of the poison would improve survival rates and prevent lethal poisoning cases. In this study, molecularly imprinted photonic crystal (MIPC) sensor was prepared by combining molecular imprinting with photonic crystal templates and tested towards the detection of α-amanitin. In this process, synthesized moiety of α–amanitin was utilized as template, dispersed SiO2 colloidal photonic crystal as carrier, methacrylic acid (MAA) as functional monomer, and ethylene glycol dimethacrylate (EDGMA) as crosslinker. The adsorption behavior of MIPC towards α-amanitin in ethanol solution showed shifts in diffraction peaks of MIPC upon binding with α-amanitin molecules. The reflection peak wavelength varied linearly with α-amanitin concentration according to the correlation formula: λ = 15.417c+489.17 (R2 = 0.9985). The recognition process was accompanied by gradual color change in MIPC film. The prepared MIPC sensor possessed wide linear range (10−9–10−3 mg L−1), change in visual color, low detection limit (10−10 mg L−1), short response time (2 min), and good reusability. The MIPC film was then tested towards the detection of α-amanitin in real biological samples (mushroom, urine, and serum) and showed reasonable shift in diffraction peaks and color change upon soaking in solutions spiked with α-amanitin at 10−6 mg L−1 and 10−3 mg L−1, suggesting the suitability of the film for the rapid identification of α-amanitin in complex sample matrices. Overall, the proposed sensor looks promising for the rapid identification of α-amanitin in clinical analysis and food poisoning.Graphical abstractImage 1
       
  • A dual-responsive biosensor for blood lead detection
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Huan Chen, Shuibin Shao, Yueqi Yu, Yangyang Huang, Xiaotan Zhu, Shiyan Zhang, Jin Fan, Guo Yong Yin, Bo Chi, Mimi Wan, Chun MaoSimple and accurate detection of trace heavy metals in blood is very important. A novel dual-responsive electrochemical/fluorescent biosensor based on magnetic hyperbranched polyamide with heparin modification (MHPAM-H) for blood lead detection has been successfully developed. Upon conjugated with blood lead ions, dual-biosensor could not only display electrochemical signal but also fluorescence signal owing to the enriched amino groups, cavity structure, and good fluorescence properties of HPAM. Blood biocompatibility, construction of the dual-responsive biosensor, electrochemical/fluorescent detection of lead ions in water phase and blood condition, selectivity and stability of the dual-responsive biosensor were investigated in detail. The proposed dual-responsive biosensor displays good linear relationship (1.5 pM- 4.8 × 103 pM for electrochemical detection and 0.5 pM-4.8 × 103 pM for fluorescent detection) with low detection limit (4.4 pM for electrochemical detection and 1.0 pM for fluorescent detection) for blood lead, providing potential application for blood lead detection in the future.Graphical abstractImage 1
       
  • Label-free peptide nucleic acid biosensor for visual detection of multiple
           strains of influenza A virus suitable for field applications
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Naveen Kumar, Sandeep Bhatia, Atul Kumar Pateriya, Richa Sood, S. Nagarajan, Harshad V. Murugkar, Satish Kumar, Praveen Singh, Vijendra Pal SinghAccurate and rapid diagnosis of Influenza A viruses (IAVs) is challenging because of multiple strains circulating in humans and animal populations, and the emergence of new strains. In this study, we demonstrate a simple and rapid strategy for visual detection of multiple strains of IAVs (H1 to H16 subtypes) using peptide nucleic acid (PNA) as a biosensor and unmodified gold nanoparticles (AuNPs) as a reporter. The design principle of the assay is based on the color change on account of free PNA-induced aggregation of AuNPs in the presence of non-complementary viral RNA sequence and vice-versa. The assay could detect IAV RNA with a visual limit of detection of 2.3 ng. The quantification of RNA with a considerable accuracy on a simple spectrophotometer was achieved on plotting the PNA-induced colorimetric changes (absorption ratio of A640/A520) in the presence of a varying concentration of complementary RNA. As a proof-of-concept, the visual assay was validated on 419 avian clinical samples and receiver operating characteristic (ROC) curve analysis showed a high diagnostic specificity (96.46%, 95% CI = 93.8 to 98.2) and sensitivity (82.41%, 95% CI = 73.9 to 89.1) when RT-qPCR was used as reference test. Hence, the simplicity, rapidity, and universality of this strategy make it a potential candidate visual assay for clinical diagnosis and surveillance of IAVs, especially in the resource-limited settings. The proposed strategy establishes new avenues for developing a simple and rapid diagnostic system for viral infections and biomolecules.Graphical abstractImage 1
       
  • High performance tube sensor based on PANI/Eu3+ nanofiber for low-volume
           NH3 detection
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Wenqian Zhang, Guishun Li, Changkun She, Aiyun liu, Jianing Cheng, Hongkai Li, Shaohua Liu, Chengbin Jing, Ya Cheng, Junhao ChuA novel polyaniline (PANI)/Eu3+ nanofiber sensing film was prepared in the presence of Eu(NO3)3 which serves as structure-directed agent. The morphological, component, crystallinity and electrochemical properties were carried out by using Scanning Electron Microscope (SEM), Energy-Dispersive X-ray (EDX), Fourier Transform Infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Brunauer-Emmett-Teller (BET) techniques. The results indicated the nanofiber-like network with porous structure appeared in the PANI embedded by Eu3+ ions, thereby leading to large specific surface area. Furthermore, the PANI/Eu3+ nanofibers were grown onto the inner wall of capillary glass to form the tube sensor. By the sensing measurements, this tube sensor enabled the detection of low-volume (0.3 mL) NH3 for response 435% at concentration of 0.25 ppm with a short response time (5 s) and recovery time (5 s), and the performances of reproducibility and selectivity were also excellent. The above results demonstrated the potential application of PANI/Eu3+ tube sensor for low-volume NH3 gas.Graphical abstractImage 1
       
  • Simple and accurate visual detection of single nucleotide polymorphism
           based on colloidal gold nucleic acid strip biosensor and primer-specific
           PCR
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Hai-Bo Wang, Li-Hong Ma, Ting Zhang, Kai-Chen Huang, Yuan-Di Zhao, Tian-Cai LiuSingle nucleotide polymorphism (SNP) was associated with many human diseases, therefore, SNP detection was important for early diagnosis and clinical prognosis. Herein, a simple and accurate method for visual detection SNP sites (A/A, G/G, A/G) in CYP1A1 gene related to cancers based on colloidal gold nucleic acid strip biosensor and primer-specific polymerase chain reaction (PCR) was established. This method could directly distinguish SNP sites on strip biosensor by introducing twice PCR amplifications. The second PCR (primer-specific PCR) was performed using specific product of the first PCR as template, thus this twice PCR could reduce non-specific amplification greatly and obtain target product. In addition, single-strand or double-strand DNA (ssDNA or dsDNA) was accurately produced by introducing mismatched base at the 3’ end of forward primers in primer-specific PCR. The designed strip biosensor could only combine with the ssDNA, thus visual detection of SNP could be achieved within 10 min by color difference of a pair of strips. 61 human blood samples by this method were identical with those of pyrosequencing. This method had the advantages of rapid, visual and low-cost and was expected to be applied in medical diagnosis.Graphical abstractImage 1
       
  • Glassy carbon electrodes modified with reduced graphene oxide-MoS2-poly
           (3, 4-ethylene dioxythiophene) nanocomposites for the non-enzymatic
           detection of nitrite in water and milk
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Rajesh Madhuvilakku, Srinivasan Alagar, Ramalakshmi Mariappan, Shakkthivel PiramanThe detrimental effect of (NO2−) on environment, a sensitive and selective detection of nitrite (NO2−) ions with point-to-care device is need to be fabricated. Herein, we report the non-enzymatic nitrite sensor using a novel reduced graphene oxide/molybdenum disulfide/poly (3, 4-ethylene dioxythiophene) (rGO/MoS2/PEDOT) nanocomposite electrode. The rGO/MoS2/PEDOT nanocomposite was synthesized using facile and cost-effective hydrothermal and polymerization approaches. The characteristics of rGO-MoS2-PEDOT nanocomposite was investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analyses. The rGO-MoS2-PEDOT nanocomposite modified glassy carbon electrode (GCE) was directly used for electrocatalytic detection of nitrite ions present in the solution. TEM images show the PEDOT nanoparticles with an average size of 100–120 nm are uniformly covered on the outer face of rGO-MoS2 nanosheets. The interaction between the PEDOT and rGO-MoS2 is evidenced in the FTIR, XRD and XPS studies, and they produced synergistic effect, resulting enhanced electrocatalytic performance activity towards oxidation of nitrite. Under optimized conditions, the fabricated electrode exhibited remarkably good sensitivity (874.19 μA μM−1 cm−2), low detection limit (LOD) (0.059 μM, S/N = 3), wide linear range (0.001–1 mM) of nitrite with desirable selectivity, long-term stability and reproducibility. Furthermore, the practical feasibility of the fabricated sensor is validated by the successful detection of nitrite ion in some water and milk samples with excellent correlation. Thus, feasible easier synthesis method was adopted first time to fabricate rGO-MoS2-PEDOT nanocomposite nitrite sensor in the milk and water samples with enhanced selectivity, sensitivity and LOD.Graphical abstractImage 1
       
  • Cascade signal amplification sensing strategy for highly specific and
           sensitive detection of homologous microRNAs in different molecular
           subtypes of breast cancer
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Ling Qiao, Chuanli Wu, Zhewei Cai, Xingchen Wu, Ping Wu, Chenxin CaiDiscriminative identification of homologous miRNAs in miRNA family with high specificity and sensitivity is crucial for accurate classification, diagnosis and prognosis of breast cancer. Herein, we report a reliable, sensitive, and selective assay by coupling fluorescence resonance energy transfer (FRET) with cascade signal amplification. The strategy is developed by designing two programmable DNA probes that can be triggered to shift from “off” to “on” state in a cascade hybridization reaction in the presence of target miRNA let-7a, leading to the generation of an amplified signal. The assay can detect concentrations as low as ∼3.0 pM let-7a and discriminate let-7a from other highly homologous members in the let-7 miRNA family. Moreover, it can also be used to determine let-7a levels at single-cell resolution and evaluate the drug efficacy of let-7a expression among various molecular types of breast cancer cell lines. The advantage of this assay is a combined result of signal generation and amplification triggered by target miRNA, which can satisfy an assay of analogous miRNA in a downregulated manner with high specificity. It has promising potential as a selective assay for homologous miRNAs in precision medicine.Graphical abstractImage 1
       
  • The multiple facets of flow analysis. A tutorial
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Elias A.G. Zagatto, Fábio R.P. RochaThe amazing development of flow analysis has led to a loss of conceptual uniformity and to the proposals of a number of modalities, each assigned to an acronym, and this aspect may hinder further developments in the field. As any sample handling step of a flow-based analytical procedure can be accomplished in different ways, there are multiple facets associated to it. This tutorial is focused on the critical evaluation of these facets and the proposal of a novel way to present the flow analyzers, disregarding or even avoiding the need for specifying flow modalities and acronyms.Graphical abstractImage 1
       
  • A novel smartphone-based CD-spectrometer for high sensitive and
           cost-effective colorimetric detection of ascorbic acid
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Liubing Kong, Ying Gan, Tao Liang, Longjie Zhong, Yuxiang Pan, Dmitry Kirsanov, Andrey Legin, Hao Wan, Ping WangAs a powerful tool for medical diagnosis and bioanalysis, conventional optical spectrometers are generally expensive, bulky and always require an accompanying data processing device. In this work, we developed a novel smartphone-based CD-spectrometer (SCDS) for high sensitive and ultra-portable colorimetric analysis, with the advantage of cost-effective and simplicity. The distance between the light source and slit, the structure of SCDS and the parameters of camera in the smartphone were all optimized to ensure the best analytical performance. Besides, the SCDS employed HSV color model and utilized the overall intensity calculated by summing V-value of adjacent position for the absorbance measurement. In this way the errors caused by the low resolution of CD-grating can effectively be eliminated to promote the sensitivity of the SCDS. The performance of the SCDS was first validated for colorimetric detection of BSA with a detection limit of 0.0073 mg/mL, which is superior compared to that of the microtiter plate reader (MTPR). Moreover, by combining with 3,3′,5,5′-tetramethylbenzidine-manganese dioxide (TMB-MnO2) nanosheets reaction, a high sensitive and specific system for ascorbic acid detection was established. The SCDS gives a detection range from 0.6250 μM to 40 μM with a detection limit of 0.4946 μM for AA detection. Compared to other studies, the SCDS features wide detection range and very low detection limit with low cost instrument. Therefore, the SCDS will be an ideal and promising colorimetric system for point-of-care (POC) application in food security, disease diagnosis and environmental monitoring.Graphical abstractImage 1
       
  • Ultrasensitive detection of miRNA based on efficient immobilization of
           probe and electrochemiluminescent quenching of Ru(bpy)3 2+ by methylene
           blue
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Liping Lu, Chang Liu, Wujian Miao, Xiayan Wang, Guanghsheng GuoA high performance miRNA biosensor based on effective click chemistry assembly of a Ru(bpy)32+ labeled DNA probe and efficient electrochemiluminescence (ECL) quenching of the Ru(bpy)32+/BDEA (BDEA = N-butyldiethanolamine) system by surface-confined electroactive methylene blue (MB) dye is reported. When the target miRNA was present, the ECL signal instantly changed from “light off” to “light on” status. Using the specific miRNA let-7d as the target analyte, this biosensor provided sensitive detection over approximately six orders of magnitude (10 fM-10 nM), with a limit of detection of 10 fM (S/N = 3). Detailed study of the ECL quenching behavior of the Ru(bpy)32+/BDEA system by MB in solution suggested that the ECL quenching involves a combination of photoluminescence dynamic quenching and quenching processes directly associated with the redox reactions, as well as resonance energy transfer. A large binding constant of 4.7 × 1011 M−1 between let-7d and the DNA hairpin was estimated using an ECL-based extended Langmuir isotherm model, suggesting remarkably strong binding of the target to the probe. Furthermore, our biosensor exhibited excellent specificity and reproducibility. Using the developed system, the concentration of the target miRNA extracted from the A549 cell line could be obtained, demonstrating the potential application of the developed biosensor to practical biological sample analysis.Graphical abstractImage 1
       
  • Label-assisted chemical adsorption triggered conversion of electroactivity
           of sensing interface to achieve the Ag/AgCl process for ultrasensitive
           detection of CA 19-9
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Nana Zhang, Dongsheng Zhang, Changshun Chu, Zhanfang MaEfficient strategies in enhancing sensitivity are pivotal to ultrasensitive detection of tumor markers. In this work, based on the strategy of label-assisted chemical adsorption triggered conversion of electroactivity of sensing interface, a Ag/AgCl process was achieved to enhance sensitivity of the constructed sandwich-type amperometric immunosensor for ultrasensitive detection of carbohydrate antigen 19–9 (CA19-9). Briefly, polydopamine-Ag nanoparticles (PDA-Ag NPs), as signal precursor, combined with labeling antibody were served as labels and graphene oxide-melamine (GO-MA) substrate with chemical absorption capacity was applied as smart sensing interface. After successfully incubating labels, there was primitively no current response due to the poor conductivity between labels and electrode. However, in the presence of H2O2, Ag NPs from labels can be etched into Ag ions, which were adsorbed by GO-MA to form GO-MA-Ag as electroactive substrate. Then, the substrate exhibited a sharp and stable electrochemistry peak of solid-state Ag/AgCl process in the buffer containing KCl. The sensitivity toward detection of CA19-9 was notably enhanced based on the appearance of sharp peak. Under optimum conditions, the designed immunosensor demonstrated a wide working range from 0.0001 to 100 U mL−1 and an ultralow detection limit 0.032 mU mL−1. Thus, utilizing this strategy to construct immunosensor was highly promising in clinical diagnosis for ultrasensitive detection of tumor makers.Graphical abstractImage 1
       
  • Cobalt-iron selenides embedded in porous carbon nanofibers for
           simultaneous electrochemical detection of trace of hydroquinone, catechol
           and resorcinol
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Duanduan Yin, Jian Liu, Xiangjie Bo, Liping GuoIn this study, cobalt-iron selenides embedded in porous carbon nanofibers (CoFe2Se4/PCF), derived from Prussian blue analogues, was prepared as a novel phenolic sensor. The obtained CoFe2Se4/PCF nanocomposites show three-dimensional (3D) networks nanostructures that can supply a desirable conductive network to accelerate electron transfer and avoid the aggregation of CoFe2Se4 nanoparticles. Electrochemical detection of hydroquinone (HQ), catechol (CC) and resorcinol (RS), at CoFe2Se4/PCF modified glassy carbon electrode (GCE) were researched. The results show the obtained 3D CoFe2Se4/PCF/GCE exhibits excellent electrochemical properties towards the simultaneous testing trace of HQ, CC and RS. The obtained electrode provides wide linear ranges of 0.5–200, 0.5–190 and 5–350 μM and low detection limit of 0.13, 0.15 and 1.36 μM for HQ, CC and RS, respectively. The as-prepared phenolic sensor displays satisfied selectivity and long-term storage stability. In addition, the constructed sensor can be used to determine HQ, CC and RS in actual samples.Graphical abstractCoFe2Se4/PCF composites were prepared, which used to simultaneously detect HQ, CC and RS.Image 1
       
  • Competitive electrochemical immunosensor for the detection of unfolded p53
           protein in blood as biomarker for Alzheimer’s disease
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Olaya Amor-Gutiérrez, Estefanía Costa-Rama, Noemi Arce-Varas, Carmen Martínez-Rodríguez, Antonello Novelli, María Teresa Fernández-Sánchez, Agustín Costa-GarcíaAlzheimer's disease is one of the most common causes of dementia nowadays, and its prevalence increases over time. Because of this and the difficulty of its diagnosis, accurate methods for the analysis of specific biomarkers for an early diagnosis of this disease are much needed. Recently, the levels of unfolded isoform of the multifunctional protein p53 in plasma have been proved to increase selectively in Alzheimer's Disease patients in comparison with healthy subjects, thus entering the list of biomarkers that can be used for the diagnosis of this illness.We present here the development of an electrochemical immunosensor based on nanostructured screen-printed carbon electrodes for the quantification of unfolded p53 in plasma samples. The sensor shows a suitable linear range (from 2 to 50 nM) for its application in real blood samples and a very low limit of detection (0.05 nM). The concentration of unfolded p53 has been accurately detected in plasma of elderly people in healthy conditions, subjects with mild cognitive impairment (MCI) and Alzheimer's Disease (AD) subjects, obtaining results with no significant differences to those provided by an ELISA assay. These results support the possibility of measuring unfolded p53 levels with a cheap, simple and miniaturized device with a promising future for point-of-care applications in the early diagnosis of Alzheimer's dementia.Graphical abstractImage 1
       
  • Exploring the upper particle size limit for field flow fractionation
           online with ICP-MS to address the challenges of water samples from the
           Taihu Lake
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Jingjing Yang, Ping Tan, Tianyin Huang, Volker NischwitzRegular algal blooms are occurring in Taihu lake, which may be triggered by resuspension of sediments containing relevant amounts of phosphorus. Therefore, our study aims at quantification of phosphorus concentrations bound to suspended particulate matter in Taihu water samples to investigate this hypothesis. A field flow fractionation (FFF) method online with ICP-MS detection was developed to achieve an overview on particulate fractions of phosphorus and related elements including Fe, Al and C from the low nanometer to the low micrometer size range. Mass balance of dissolved and particulate elemental contents was established for quality control purpose and indicated low recovery of Fe, Al and P. Complementary determination of volume based particle size distribution by dynamic imaging analysis showed a majority of particle volume and thus mass in particles with size>5 μm. In order to address this challenge, the upper particle size limit of FFF online with ICP-MS was for the first time investigated in detail using well characterised monodisperse latex particles as model for organic matter in the low micrometer size range including microalgae. The effect of pre-filtration of the sample as well as the contribution of sample introduction via three different interfaces including micromist nebuliser/spray chamber, direct injection nebulisation and APEX with heated spray chamber and solvent removal by condensation on the particulate carbon recovery was studied by ICP-MS detection. The same instrumental setup was also applied for the characterisation of particulate elemental contents in the Taihu water samples as far as possible. Significant improvement of the detected particulate fraction in Taihu water samples was achieved by increasing the membrane pore size for pre-filtration and by using the APEX for introduction of the eluate from FFF into ICP-MS.Graphical abstractImage 1
       
  • Infrared ion spectroscopy: New opportunities for small-molecule
           identification in mass spectrometry - A tutorial perspective
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): Jonathan Martens, Rianne E. van Outersterp, Rob J. Vreeken, Filip Cuyckens, Karlien L.M. Coene, Udo F. Engelke, Leo A.J. Kluijtmans, Ron A. Wevers, Lutgarde M.C. Buydens, Britta Redlich, Giel Berden, Jos OomensCombining the individual analytical strengths of mass spectrometry and infrared spectroscopy, infrared ion spectroscopy is increasingly recognized as a powerful tool for small-molecule identification in a wide range of analytical applications. Mass spectrometry is itself a leading analytical technique for small-molecule identification on the merit of its outstanding sensitivity, selectivity and versatility. The foremost shortcoming of the technique, however, is its limited ability to directly probe molecular structure, especially when contrasted against spectroscopic techniques. In infrared ion spectroscopy, infrared vibrational spectra are recorded for mass-isolated ions and provide a signature that can be matched to reference spectra, either measured from standards or predicted using quantum-chemical calculations. Here we present an overview of the potential for this technique to develop into a versatile analytical method for identifying molecular structures in mass spectrometry-based analytical workflows. In this tutorial perspective, we introduce the reader to the technique of infrared ion spectroscopy and highlight a selection of recent experimental advances and applications in current analytical challenges, in particular in the field of untargeted metabolomics. We report on the coupling of infrared ion spectroscopy with liquid chromatography and present experiments that serve as proof-of-principle examples of strategies to address outstanding challenges.Graphical abstractImage 1
       
  • Outside Front Cover
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s):
       
  • Influence of photo-initiators in the preparation of methacrylate monoliths
           into poly(ethylene-co-tetrafluoroethylene) tubing for microbore HPLC
    • Abstract: Publication date: 6 January 2020Source: Analytica Chimica Acta, Volume 1093Author(s): M. Catalá-Icardo, S. Torres-Cartas, E.F. Simó-Alfonso, J.M. Herrero-MartínezIn this study, poly(butyl methacrylate-co-ethyleneglycol dimethacrylate) polymeric monoliths were in situ developed within 0.75 mm i.d. poly(ethylene-co-tetrafluoroethylene) (ETFE) tubing by UV polymerization via three different free-radical initiators (α,α’-azobisisobutyronitrile (AIBN), 2,2-dimethoxy-2-phenylacetophenone (DMPA) and 2-methyl-4′-(methylthio)-2-morpholinopropiophenone (MTMPP). The influence of the nature of each photo-initiator and irradiation time on the morphological features of the polymer was investigated by scanning electron microscopy, and the chromatographic properties of the resulting microbore columns were evaluated using alkyl benzenes as test substances. The beds photo-initiated with MTMPP gave the best performance (minimum plate heights of 38 μm for alkyl benzenes) and exhibited a satisfactory reproducibility in the chromatographic parameters (RSD 
       
 
 
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