for Journals by Title or ISSN
for Articles by Keywords
help

Publisher: Elsevier   (Total: 3049 journals)

 A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  

        1 2 3 4 5 6 7 8 | Last   [Sort by number of followers]   [Restore default list]

Showing 1 - 200 of 3089 Journals sorted alphabetically
A Practical Logic of Cognitive Systems     Full-text available via subscription   (Followers: 7)
AASRI Procedia     Open Access   (Followers: 15)
Academic Pediatrics     Hybrid Journal   (Followers: 25, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 22, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 86, SJR: 1.109, h-index: 94)
Accounting Forum     Hybrid Journal   (Followers: 25, SJR: 0.612, h-index: 27)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 30, SJR: 2.515, h-index: 90)
Achievements in the Life Sciences     Open Access   (Followers: 4)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 5, SJR: 0.338, h-index: 19)
Acta Astronautica     Hybrid Journal   (Followers: 363, SJR: 0.726, h-index: 43)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Biomaterialia     Hybrid Journal   (Followers: 25, SJR: 2.02, h-index: 104)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 1)
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 8, SJR: 0.172, h-index: 29)
Acta Haematologica Polonica     Free   (SJR: 0.123, h-index: 8)
Acta Histochemica     Hybrid Journal   (Followers: 3, SJR: 0.604, h-index: 38)
Acta Materialia     Hybrid Journal   (Followers: 229, SJR: 3.683, h-index: 202)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.615, h-index: 21)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.442, h-index: 21)
Acta Oecologica     Hybrid Journal   (Followers: 10, SJR: 0.915, h-index: 53)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription   (Followers: 1)
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 3, SJR: 0.311, h-index: 16)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 1)
Acta Poética     Open Access   (Followers: 4)
Acta Psychologica     Hybrid Journal   (Followers: 24, SJR: 1.365, h-index: 73)
Acta Sociológica     Open Access  
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.059, h-index: 77)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 4)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 3)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 4, SJR: 0.383, h-index: 19)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 2)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 5, SJR: 0.141, h-index: 3)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 4, SJR: 0.112, h-index: 2)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 4)
Acute Pain     Full-text available via subscription   (Followers: 13)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.967, h-index: 57)
Addictive Behaviors     Hybrid Journal   (Followers: 15, SJR: 1.514, h-index: 92)
Addictive Behaviors Reports     Open Access   (Followers: 6)
Additive Manufacturing     Hybrid Journal   (Followers: 7, SJR: 1.039, h-index: 5)
Additives for Polymers     Full-text available via subscription   (Followers: 21)
Advanced Cement Based Materials     Full-text available via subscription   (Followers: 3)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 132, SJR: 5.2, h-index: 222)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.265, h-index: 53)
Advanced Powder Technology     Hybrid Journal   (Followers: 17, SJR: 0.739, h-index: 33)
Advances in Accounting     Hybrid Journal   (Followers: 9, SJR: 0.299, h-index: 15)
Advances in Agronomy     Full-text available via subscription   (Followers: 15, SJR: 2.071, h-index: 82)
Advances in Anesthesia     Full-text available via subscription   (Followers: 26, SJR: 0.169, h-index: 4)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 3)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 6, SJR: 1.054, h-index: 35)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 11, SJR: 0.801, h-index: 26)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22, SJR: 1.286, h-index: 49)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 16, SJR: 3.31, h-index: 42)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.277, h-index: 43)
Advances in Botanical Research     Full-text available via subscription   (Followers: 3, SJR: 0.619, h-index: 48)
Advances in Cancer Research     Full-text available via subscription   (Followers: 25, SJR: 2.215, h-index: 78)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 0.9, h-index: 30)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 2.139, h-index: 42)
Advances in Cell Aging and Gerontology     Full-text available via subscription   (Followers: 4)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 27, SJR: 0.183, h-index: 23)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.665, h-index: 29)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 9, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 29, SJR: 0.938, h-index: 33)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18, SJR: 2.314, h-index: 130)
Advances in Computers     Full-text available via subscription   (Followers: 16, SJR: 0.223, h-index: 22)
Advances in Dermatology     Full-text available via subscription   (Followers: 12)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 11)
Advances in Digestive Medicine     Open Access   (Followers: 7)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Ecological Research     Full-text available via subscription   (Followers: 45, SJR: 3.25, h-index: 43)
Advances in Engineering Software     Hybrid Journal   (Followers: 26, SJR: 0.486, h-index: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 7)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 43, SJR: 5.465, h-index: 64)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 3)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 51, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Genetics     Full-text available via subscription   (Followers: 15, SJR: 2.558, h-index: 54)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 2.325, h-index: 20)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 0.497, h-index: 31)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 2, SJR: 0.396, h-index: 27)
Advances in Immunology     Full-text available via subscription   (Followers: 36, SJR: 4.152, h-index: 85)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 1.132, h-index: 42)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 3, SJR: 1.274, h-index: 27)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 4)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.764, h-index: 15)
Advances in Lipobiology     Full-text available via subscription   (Followers: 2)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Marine Biology     Full-text available via subscription   (Followers: 16, SJR: 1.645, h-index: 45)
Advances in Mathematics     Full-text available via subscription   (Followers: 10, SJR: 3.261, h-index: 65)
Advances in Medical Sciences     Hybrid Journal   (Followers: 6, SJR: 0.489, h-index: 25)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.44, h-index: 51)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 22)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 10)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 8, SJR: 0.324, h-index: 8)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 4)
Advances in Oncobiology     Full-text available via subscription   (Followers: 3)
Advances in Organ Biology     Full-text available via subscription   (Followers: 2)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15, SJR: 2.885, h-index: 45)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.148, h-index: 11)
Advances in Parasitology     Full-text available via subscription   (Followers: 7, SJR: 2.37, h-index: 73)
Advances in Pediatrics     Full-text available via subscription   (Followers: 24, SJR: 0.4, h-index: 28)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 13)
Advances in Pharmacology     Full-text available via subscription   (Followers: 15, SJR: 1.718, h-index: 58)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 0.384, h-index: 26)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.248, h-index: 11)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20, SJR: 1.5, h-index: 62)
Advances in Psychology     Full-text available via subscription   (Followers: 62)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5, SJR: 0.478, h-index: 32)
Advances in Radiation Oncology     Open Access  
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 2, SJR: 0.1, h-index: 2)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 5)
Advances in Space Research     Full-text available via subscription   (Followers: 360, SJR: 0.606, h-index: 65)
Advances in Structural Biology     Full-text available via subscription   (Followers: 8)
Advances in Surgery     Full-text available via subscription   (Followers: 7, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 30, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 16)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 13)
Advances in Virus Research     Full-text available via subscription   (Followers: 5, SJR: 1.878, h-index: 68)
Advances in Water Resources     Hybrid Journal   (Followers: 44, SJR: 2.408, h-index: 94)
Aeolian Research     Hybrid Journal   (Followers: 5, SJR: 0.973, h-index: 22)
Aerospace Science and Technology     Hybrid Journal   (Followers: 331, SJR: 0.816, h-index: 49)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.318, h-index: 36)
African J. of Emergency Medicine     Open Access   (Followers: 5, SJR: 0.344, h-index: 6)
Ageing Research Reviews     Hybrid Journal   (Followers: 8, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 417, SJR: 1.385, h-index: 72)
Agri Gene     Hybrid Journal  
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 16, SJR: 2.18, h-index: 116)
Agricultural Systems     Hybrid Journal   (Followers: 30, SJR: 1.275, h-index: 74)
Agricultural Water Management     Hybrid Journal   (Followers: 40, SJR: 1.546, h-index: 79)
Agriculture and Agricultural Science Procedia     Open Access  
Agriculture and Natural Resources     Open Access   (Followers: 2)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 55, SJR: 1.879, h-index: 120)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.434, h-index: 14)
Air Medical J.     Hybrid Journal   (Followers: 5, SJR: 0.234, h-index: 18)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.285, h-index: 3)
Alcohol     Hybrid Journal   (Followers: 11, SJR: 0.922, h-index: 66)
Alcoholism and Drug Addiction     Open Access   (Followers: 8)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.436, h-index: 12)
Alexandria J. of Medicine     Open Access   (Followers: 1)
Algal Research     Partially Free   (Followers: 8, SJR: 2.05, h-index: 20)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.46, h-index: 29)
Allergology Intl.     Open Access   (Followers: 4, SJR: 0.776, h-index: 35)
Alpha Omegan     Full-text available via subscription   (SJR: 0.121, h-index: 9)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 9, SJR: 0.158, h-index: 9)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 46, SJR: 4.289, h-index: 64)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 4)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 4)
Ambulatory Pediatrics     Hybrid Journal   (Followers: 5)
American Heart J.     Hybrid Journal   (Followers: 49, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 48, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 40, SJR: 0.574, h-index: 65)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 9, SJR: 1.091, h-index: 45)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 14, SJR: 1.653, h-index: 93)
American J. of Human Genetics     Hybrid Journal   (Followers: 32, SJR: 8.769, h-index: 256)
American J. of Infection Control     Hybrid Journal   (Followers: 26, SJR: 1.259, h-index: 81)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 32, SJR: 2.313, h-index: 172)
American J. of Medicine     Hybrid Journal   (Followers: 46, SJR: 2.023, h-index: 189)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 199, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 59, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 6)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.249, h-index: 88)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, h-index: 45)
American J. of Pathology     Hybrid Journal   (Followers: 27, SJR: 2.653, h-index: 228)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 25, SJR: 2.764, h-index: 154)
American J. of Surgery     Hybrid Journal   (Followers: 35, SJR: 1.286, h-index: 125)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.653, h-index: 70)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 6)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.066, h-index: 51)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 58, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 12)
Anales de Cirugia Vascular     Full-text available via subscription  
Anales de Pediatría     Full-text available via subscription   (Followers: 2, SJR: 0.209, h-index: 27)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription   (SJR: 0.104, h-index: 3)
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 4, SJR: 2.577, h-index: 7)
Analytica Chimica Acta     Hybrid Journal   (Followers: 37, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 167, SJR: 0.725, h-index: 154)
Analytical Chemistry Research     Open Access   (Followers: 8, SJR: 0.18, h-index: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 12)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 1)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 22, SJR: 0.421, h-index: 40)
Angiología     Full-text available via subscription   (SJR: 0.124, h-index: 9)
Angiologia e Cirurgia Vascular     Open Access  

        1 2 3 4 5 6 7 8 | Last   [Sort by number of followers]   [Restore default list]

Journal Cover Analytica Chimica Acta
  [SJR: 1.548]   [H-I: 152]   [37 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0003-2670 - ISSN (Online) 1873-4324
   Published by Elsevier Homepage  [3049 journals]
  • Low-background and visual detection of antibiotic based on
           target-activated colorimetric split peroxidase DNAzyme coupled with dual
           nicking enzyme signal amplification
    • Authors: Xuejun Cui; Rongguo Li; Xiaofei Liu; Jingfeng Wang; Xueqi Leng; Xiaolei Song; Qianqian Pei; Yu Wang; Su Liu; Jiadong Huang
      Pages: 1 - 8
      Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997
      Author(s): Xuejun Cui, Rongguo Li, Xiaofei Liu, Jingfeng Wang, Xueqi Leng, Xiaolei Song, Qianqian Pei, Yu Wang, Su Liu, Jiadong Huang
      Herein, we have reported the development of a simple, rapid, and low cost colorimetric method for the detection of antibiotic based on target-activated split peroxidase DNAzyme coupled with dual nicking enzyme signal amplification (NESA). To lower background signal in G-quadruplex DNAzyme-based detection, the two split G-rich parts are caged into two different hairpin probes, respectively, preventing the two parts from assembling into the G-quadruplex structure. By the combination of restriction endonuclease-assisted cleavage reaction with the spilt G-quadruplex probes, target-modulated release of the two split G-rich parts is achieved, affording high specificity of antibiotic detection. Our strategy features with several aspects. First, the less background signal produced by the self-assembly of G-quadruplex in the absence of target is effectively eliminated owing to the pre-blocking of the two split G-rich parts. Second, dual NESA coupled G-quadruplex DNAzyme amplification strategy is integrated with colorimetric assay of antibiotic, which significantly improves the detection sensitivity. Third, peroxidase-mimicking DNAzyme is used as biocatalyst in our reaction system, which can catalyze the oxidation of 2,2' - azino - bis (3 - ethylbenzothiozoline - 6 - sulfonic acid) (ABTS2−) mediated by H2O2 to generate the colored radical anion (ABTS•-), allowing to low cost and visual detection of antibiotic by the naked eye. Under optimized conditions, the results revealed the proposed biosensor exhibits excellent specificity and sensitivity toward kanamycin with a detection limit as low as 14.7 pM. Hence, the target-activated split G-quadruplex DNAzyme and dual NESA-based strategy provides a useful and practical platform for antibiotic residues determination and other analytes detection in bio-analysis.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.009
      Issue No: Vol. 997 (2017)
       
  • Surface sieving coordinated IMAC material for purification of His-tagged
           proteins
    • Authors: Senwu Li; Kaiguang Yang; Lukuan Liu; Baofeng Zhao; Yuanbo Chen; Xiao Li; Lihua Zhang; Yukui Zhang
      Pages: 9 - 15
      Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997
      Author(s): Senwu Li, Kaiguang Yang, Lukuan Liu, Baofeng Zhao, Yuanbo Chen, Xiao Li, Lihua Zhang, Yukui Zhang
      Tailor-made materials for the purification of proteins with His-tag was designed through synergizing the selectivity of surface sieving and metal ion affinity. By excluding impurity proteins out of the surface polymer network, such materials could purify His-tagged proteins from the crude cell lysis with purity up to 90%, improved by 14% compared to that obtained by the commercial metal chelating affinity materials. This study might promote the His-tagged protein purification to a new level.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.021
      Issue No: Vol. 997 (2017)
       
  • Simultaneous determination of renal function biomarkers in urine using a
           validated paper-based microfluidic analytical device
    • Authors: Eduardo Luiz Rossini; Maria Izabel Milani; Emanuel Carrilho; Leonardo Pezza; Helena Redigolo Pezza
      Pages: 16 - 23
      Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997
      Author(s): Eduardo Luiz Rossini, Maria Izabel Milani, Emanuel Carrilho, Leonardo Pezza, Helena Redigolo Pezza
      In this paper, we describe a validated paper-based microfluidic analytical device for the simultaneous quantification of two important biomarkers of renal function in urine. This paper platform provides an inexpensive, simple, and easy to use colorimetric method for the quantification of creatinine (CRN) and uric acid (UA) in urine samples. The microfluidic paper-based analytical device (μPAD) consists of a main channel with three identical arms, each containing a circular testing zone and a circular uptake zone. Creatinine detection is based on the Jaffé reaction, in which CRN reacts with picrate to form an orange-red product. Uric acid quantification is based on the reduction of Fe3+ to Fe2+ by UA, which is detected in a colorimetric reaction using 1,10-phenanthroline. Under optimum conditions, obtained through chemometrics, the concentrations of the analytes showed good linear correlations with the effective intensities, and the method presented satisfactory repeatability. The limits of detection and the linear ranges, respectively, were 15.7 mg L−1 and 50–600 mg L−1 for CRN and 16.5 mg L−1 and 50–500 mg L−1 for UA. There were no statistically significant differences between the results obtained using the μPAD and a chromatographic comparative method (Student's t-test at 95% confidence level).
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.018
      Issue No: Vol. 997 (2017)
       
  • A fast and low-cost microfabrication approach for six types of
           thermoplastic substrates with reduced feature size and minimized bulges
           using sacrificial layer assisted laser engraving
    • Authors: Longjun Gu; Guodong Yu; Cheuk-Wing Li
      Pages: 24 - 34
      Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997
      Author(s): Longjun Gu, Guodong Yu, Cheuk-Wing Li
      Since polydimethylsiloxane (PDMS) is notorious for its severe sorption to biological compounds and even nanoparticles, thermoplastics become a promising substrate for microdevices. Although CO2 laser engraving is an efficient method for thermoplastic device fabrication, it accompanies with poor bonding issues due to severe bulging and large feature size determined by the diameter of laser beam. In this study, a low-cost microfabrication method is proposed by reversibly sealing a 1 mm thick polymethylmethacrylate (PMMA) over an engraving substrate to reduce channel feature size and minimize bulges of laser engraved channels. PMMA, polycarbonate (PC), polystyrene (PS), perfluoroalkoxy alkane (PFA), cyclic-olefin polymers (COP) and polylactic acid (PLA) were found compatible with this sacrificial layer assisted laser engraving technique. Microchannel width as small as ∼40 μm was attainable by a laser beam that was 5 times larger in diameter. Bulging height was significantly reduced to less 5 μm for most substrates, which facilitated leak proof device bonding without channel deformation. Microdevices with high aspect ratio channels were prepared to demonstrate the applicability of this microfabrication method. We believe this fast and low-cost fabrication approach for thermoplastics will be of interest to researchers who have encountered problem with polydimethylsiloxane based microdevices in their applications.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.030
      Issue No: Vol. 997 (2017)
       
  • A separable surface-enhanced Raman scattering substrate modified with
           MIL-101 for detection of overlapping and invisible compounds after
           thin-layer chromatography development
    • Authors: Bin bin Zhang; Yi Shi; Hui Chen; Qing xia Zhu; Feng Lu; Ying wei Li
      Pages: 35 - 43
      Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997
      Author(s): Bin bin Zhang, Yi Shi, Hui Chen, Qing xia Zhu, Feng Lu, Ying wei Li
      By coupling surface-enhanced Raman spectroscopy (SERS) with thin-layer chromatography (TLC), a powerful method for detecting complex samples was successfully developed. However, in the TLC-SERS method, metal nanoparticles serving as the SERS-active substrate are likely to disturb the detection of target compounds, particularly in overlapping compounds after TLC development. In addition, the SERS detection of compounds that are invisible under both visible light and UV254/365 after TLC development is still a significant challenge. In this study, we demonstrated a facile strategy to fabricate a TLC plate with metal-organic framework-modified gold nanoparticles as a separable SERS substrate, on which all separated components, including overlapping and invisible compounds, could be detected by a point-by-point SERS scan along the developing direction. Rhodamine 6G (R6G) was used as a probe to evaluate the performance of the substrate. The results indicated that the substrate provided good sensitivity and reproducibility, and optimal SERS signals could be collected in 5 s. Furthermore, this new substrate exhibited a long shelf life. Thus, our method has great potential for the sensitive and rapid detection of overlapping and invisible compounds in complex samples after TLC development.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.006
      Issue No: Vol. 997 (2017)
       
  • Label-free determination of prostate specific membrane antigen in human
           whole blood at nanomolar levels by magnetically assisted surface enhanced
           Raman spectroscopy
    • Authors: Zuzana Chaloupková; Anna Balzerová; Jitka Bařinková; Zdenka Medříková; Pavel Šácha; Petr Beneš; Václav Ranc; Jan Konvalinka; Radek Zbořil
      Pages: 44 - 51
      Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997
      Author(s): Zuzana Chaloupková, Anna Balzerová, Jitka Bařinková, Zdenka Medříková, Pavel Šácha, Petr Beneš, Václav Ranc, Jan Konvalinka, Radek Zbořil
      Prostate cancer is one of the most common cancers among men and can in its later stages cause serious medical problems. Due to the limited suitability of current diagnostic biochemical markers, new biomarkers for the detection of prostate cancer are highly sought after. An ideal biomarker should serve as a reliable prognostic marker, be applicable for early diagnosis, and be applicable for monitoring of therapeutic response. One potential candidate is glutamate carboxypeptidase II (GCPII), also known as prostate specific membrane antigen (PSMA), which has a promising role for direct imaging. GCPII is considerably over-expressed on cancerous prostatic epithelial cells; its analysis typically follows radiological or spectrophotometric principles. Its role as a biomarker present in blood has been recently investigated and potential correlation between a concentration of GCPII and prostate cancer has been proposed. The wider inclusion of GCPII detection in clinical praxis limits mainly the time and cost per analysis. Here, we present a novel analytical nanosensor applicable to quantification of GCPII in human whole blood consisted of Fe3O4@Ag magnetic nanocomposite surface-functionalized by an artificial antibody (low-molecular-weight GCPII synthetic inhibitor). The nanocomposite allows a simple magnetic isolation of GCPII using external magnetic force and its consecutive determination by magnetically assisted surface enhanced Raman spectroscopy (MA-SERS) with a limit of detection 6 pmol. L−1. This method enables a rapid determination of picomolar concentrations of GCPII in whole human blood of healthy individuals using a standard addition method without a complicated sample pre-treatment.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.008
      Issue No: Vol. 997 (2017)
       
  • A novel fluorescence biosensor for sensitivity detection of tyrosinase and
           acid phosphatase based on nitrogen-doped graphene quantum dots
    • Authors: Zhengyi Qu; Weidan Na; Xiaotong Liu; Hua Liu; Xingguang Su
      Pages: 52 - 59
      Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997
      Author(s): Zhengyi Qu, Weidan Na, Xiaotong Liu, Hua Liu, Xingguang Su
      In this paper, we developed a sensitive fluorescence biosensor for tyrosinase (TYR) and acid phosphatase (ACP) activity detection based on nitrogen-doped graphene quantum dots (N-GQDs). Tyrosine could be catalyzed by TYR to generate dopaquinone, which could efficiently quench the fluorescence of N-GQDs, and the degree of fluorescence quenching of N-GQDs was proportional to the concentration of TYR. In the presence of ACP, l-Ascorbic acid-2-phosphate (AAP) was hydrolyzed to generate ascorbic acid (AA), and dopaquinone was reduced to l-dopa, resulting in the fluorescence recovery of the quenched fluorescence by dopaquinone. Thus, a novel fluorescence biosensor for the detection of TYR and ACP activity based on N-GQDs was constructed. Under the optimized experimental conditions, the fluorescence intensity was linearly correlated with the concentration of TYR and ACP in the range of 0.43–3.85 U mL−1 and 0.04–0.7 mU mL−1 with a detection limit of 0.15 U mL−1 and 0.014 mU mL−1, respectively. The feasibility of the proposed biosensor in real samples assay was also studied and satisfactory results were obtained.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.010
      Issue No: Vol. 997 (2017)
       
  • Facile synthesis of polyaniline-polythionine redox hydrogel: Conductive,
           antifouling and enzyme-linked material for ultrasensitive label-free
           amperometric immunosensor toward carcinoma antigen-125
    • Authors: Lihua Zhao; Zhanfang Ma
      Pages: 60 - 66
      Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997
      Author(s): Lihua Zhao, Zhanfang Ma
      Sensitivity enhancement and proteins adsorption are the common challenges faced in protein immunoassays. In this work, an ultrasensitive and protein-resistant label-free amperometric immunosening platform for carcinoma antigen-125 (CA125) based on redox polyaniline-polythionine hydrogel (PANI-PThi gel) was developed. The as-prepared hydrogel, which was facilely synthesized by electropolymerization, exhibited good conductivity and strong hydrophilicity while the sensitivity and specificity of the immunosensor can be enhanced. Furthermore, the as-prepared AuNPs functionalized PANI-PThi gel exhibited strong current signal and H2O2 electrocatalytic ability, which guaranteed a large current variable range. Based on these, the prepared immunosensor revealed a wide linear range from 0.0001 U mL−1 to 1 kU mL−1, a limit of detection of 0.00125 U mL−1 and its sensitivity was at least three-fold higher than previous works. More importantly, the prepared immunosensor exhibited excellent specificity, making it capable of assaying CA125 in human serum.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.017
      Issue No: Vol. 997 (2017)
       
  • Coupling of two centrifugeless ultrasound-assisted dispersive solid/liquid
           phase microextractions as a highly selective, clean, and efficient method
           for determination of ultra-trace amounts of non-steroidal
           anti-inflammatory drugs in complicated matrices
    • Authors: Somayeh Arghavani-Beydokhti; Maryam Rajabi; Alireza Asghari
      Pages: 67 - 79
      Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997
      Author(s): Somayeh Arghavani-Beydokhti, Maryam Rajabi, Alireza Asghari
      In this work, a new, simple, rapid, and environmentally friendly method with a high sample clean-up capability termed as centrifugeless ultrasound-assisted dispersive micro solid-phase extraction coupled with salting-out ultrasound-assisted liquid-liquid microextraction based on solidification of a floating organic droplet followed by high performance liquid chromatography is introduced for the first time. In this method, the three non-steroidal anti-inflammatory drugs diclofenac, ibuprofen, and mefenamic acid are first extracted based on an effective nanoadsorbent named as the layered double hydroxide-carbon nanotube nanohybrid. The first step provides a rapid and convenient way to separate the adsorbent from the sample matrix by a syringe nanofilter without additional centrifugation. In the next step, which is based upon the salting-out effect, after emulsification in the presence of ultrasonic irradiation, the phase separation is simply achieved through the salting-out phenomenon, and the extracting solvent is suspended on top of the sample solution. Under the optimal experimental conditions including the initial pH value of 6.0, 8.0 mg of the nanohybrid, 3 min ultrasonic time, 100 μL elution solvent (first step), secondary pH value of 3.0, 60 μL of 1-undecanol, 60 s ultrasonic time, and flow rate of 3 mL min−1 (second step), good responses were obtained for diclofenac, ibuprofen, and mefenamic acid in the concentration ranges of 0.8–2000, 0.8–2500, and 0.5–2000 ng mL−1, respectively, with low limits of detection ranging from 0.1 to 0.2 ng mL−1. The intra-day and inter-day precisions for the target analytes at the three concentration levels were in the ranges of 6.1–7.8% and 6.3–8.1%, respectively. The proposed method was also successfully applied to the biological and waste water samples, and excellent recoveries were obtained in the range of 92.9–103.1% even when the matrix was complex.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.005
      Issue No: Vol. 997 (2017)
       
  • Review of recent developments in determining volatile organic compounds in
           exhaled breath as biomarkers for lung cancer diagnosis
    • Authors: Jiemin Zhou; Zi-Ao Huang; Ujendra Kumar; David D.Y. Chen
      Pages: 1 - 9
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Jiemin Zhou, Zi-Ao Huang, Ujendra Kumar, David D.Y. Chen
      Lung cancer is the most common cause of cancer deaths, its global incidence is rising, and continuing rises are predicted. The potential to diagnose lung cancers based on the determination of volatile organic compounds (VOCs) in human breath has been attracting increasing attention with the development of new techniques and methodologies. However, despite many reports of VOC profiling in lung cancer patients, little is known about how specific biomarkers relate to the biochemical pathways involved in lung cancer development, and there is still no reliable method for diagnosing lung cancer at the early stages. This review summarizes some of the latest methods used for monitoring biomarkers in lung cancer patients, which could be applicable for clinical diagnosis. Techniques for capturing and pre-concentrating biomarkers, and the technologies used for subsequently determining them, are also discussed.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.09.021
      Issue No: Vol. 996 (2017)
       
  • Fabrication of a novel aptasensor based on three-dimensional reduced
           graphene oxide/polyaniline/gold nanoparticle composite as a novel platform
           for high sensitive and specific cocaine detection
    • Authors: Pegah Hashemi; Hasan Bagheri; Abbas Afkhami; Yalda Hosseinzadeh Ardakani; Tayyebeh Madrakian
      Pages: 10 - 19
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Pegah Hashemi, Hasan Bagheri, Abbas Afkhami, Yalda Hosseinzadeh Ardakani, Tayyebeh Madrakian
      In the present research, we have developed a novel label free aptasensor based on screen printed carbon electrode (SPCE) modified with three-dimensional magnetic reduced graphene oxide(3D-MRGO)/polyaniline(PA)/gold nanoparticle(AuNP) nanocomposite for impedimetric determination of cocaine. To achieve this goal, a specific thiolated cocaine aptamer was immobilized onto the surface of synthesized nanocomposite. The signaling mechanism of the proposed aptasensor was based on increase in the [Fe(CN)6]3-/4- charge transfer resistance (RCT) as an electrochemical probe in the presence of target analyte. In order to collect of 3D-MRGO/PA/AuNP/aptamer on the surface of working electrode easily, a new electrochemical cell was fabricated. The advantages of the new electrochemical cell configuration can be counted as reusing SPCE for several times, obtaining repeatable responses, reducing required volume of electrolyte and probe solution and making proposed method more user-friendly. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) were used for the characterization of synthesized nanocomposite and modified electrode surface. Under optimized condition, cocaine was determined in a linear concentration range from 0.09 to 85 nM with a detection limit of 0.029 nM by EIS. Also, in order to test applicability of the proposed aptasensor, it was applied to determine cocaine in urine and serum samples and satisfactory results were obtained.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.035
      Issue No: Vol. 996 (2017)
       
  • High throughput screening of phenoxy carboxylic acids with dispersive
           solid phase extraction followed by direct analysis in real time mass
           spectrometry
    • Authors: Jiaqin Wang; Jun Zhu; Ling Si; Qi Du; Hongli Li; Wentao Bi; David Da Yong Chen
      Pages: 20 - 28
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Jiaqin Wang, Jun Zhu, Ling Si, Qi Du, Hongli Li, Wentao Bi, David Da Yong Chen
      A high throughput, low environmental impact methodology for rapid determination of phenoxy carboxylic acids (PCAs) in water samples was developed by combing dispersive solid phase extraction (DSPE) using velvet-like graphitic carbon nitride (V-g-C3N4) and direct analysis in real time mass spectrometry (DART-MS). Due to the large surface area and good dispersity of V-g-C3N4, the DSPE of PCAs in water was completed within 20 s, and the elution of PCAs was accomplished in 20 s as well using methanol. The eluents were then analyzed and quantified using DART ionization source coupled to a high resolution mass spectrometer, where an internal standard was added in the samples. The limit of detection ranged from 0.5 ng L−1 to 2 ng L−1 on the basis of 50 mL water sample; the recovery 79.9–119.1%; and the relative standard deviation 0.23%–9.82% (≥5 replicates). With the ease of use and speed of DART-MS, the whole protocol can complete within mere minutes, including sample preparation, extraction, elution, detection and quantitation. The methodology developed here is simple, fast, sensitive, quantitative, requiring little sample preparation and consuming significantly less toxic organic solvent, which can be used for high throughput screening of PCAs and potentially other contaminants in water.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.007
      Issue No: Vol. 996 (2017)
       
  • Novel approach to high-throughput determination of endocrine disruptors
           using recycled diatomaceous earth as a green sorbent phase for thin-film
           solid-phase microextraction combined with 96-well plate system
    • Authors: Nicolas Kirschner; Adriana Neves Dias; Dilma Budziak; Cristian Berto da Silveira; Josias Merib; Eduardo Carasek
      Pages: 29 - 37
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Nicolas Kirschner, Adriana Neves Dias, Dilma Budziak, Cristian Berto da Silveira, Josias Merib, Eduardo Carasek
      A sustainable approach to TF-SPME is presented using recycled diatomaceous earth, obtained from a beer purification process, as a green sorbent phase for the determination of bisphenol A (BPA), benzophenone (BzP), triclocarban (TCC), 4-methylbenzylidene camphor (4-MBC) and 2-ethylhexyl-p-methoxycinnamate (EHMC) in environmental water samples. TF-SPME was combined with a 96-well plate system allowing for high-throughput analysis due to the simultaneous extraction/desorption up to 96 samples. The proposed sorbent phase exhibited good stability in organic solvents, as well as satisfactory analytical performance. The optimized method consisted of 240 min of extraction at pH 6 with the addition of NaCl (15% w/v). A mixture of MeOH:ACN (50:50 v/v) was used for the desorption the analytes, using a time of 30 min. Limits of detection varied from 1 μg L−1 for BzP and TCC to 8 μg L−1 for the other analytes, and R2 ranged from 0.9926 for 4-MBC to 0.9988 for BPA. This novel and straightforward approach offers an environmentally-friendly and very promising alternative for routine analysis. . The total sample preparation time per sample was approximately 2.8 min, which is a significant advantage when a large number of analytical run is required.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.09.047
      Issue No: Vol. 996 (2017)
       
  • Accurate phosphorylation site localization using phospho-brackets
    • Authors: Kaijie Xiao; Yun Shen; Shasha Li; Zhixin Tian
      Pages: 38 - 47
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Kaijie Xiao, Yun Shen, Shasha Li, Zhixin Tian
      Phosphorylation is one of the most important and widely studied protein post-translational modifications. Tandem mass spectrometry using higher-energy collisional dissociation has evolved into a state-of-the-art analytical platform for both phosphorylation identification and site localization. Tens of thousands of phosphopeptides can now be routinely identified from a single shotgun proteomics study; site localization, however, is much more complicated and many challenges still exist. Here, we report our development of P-bracket using direct experimental evidence of phospho-containing site-determining product ions for accurate site localization without the need for additional FLR control. A P-bracket is defined as a complementary product ion pair that forms a bracket to confine a phosphorylation event to a unique site. P-bracket has been successfully benchmarked with a set of six synthetic phosphopeptides with a single phosphorylation event, a set of 96 synthetic peptides and phosphopeptide reference libraries, and two HeLa phosphopeptide LC-MS/MS (HCD) datasets; Accurate phosphosite localization by P-bracket will greatly enhance identification confidence of phosphopeptides and contribute to structural and functional studies of phosphoproteins.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.09.043
      Issue No: Vol. 996 (2017)
       
  • Use of chemical conversion for determination of nitrated aromatic
           hydrocarbons using femtosecond ionization mass spectrometry
    • Authors: Takuya Fujii; Tomoko Imasaka; Totaro Imasaka
      Pages: 48 - 53
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Takuya Fujii, Tomoko Imasaka, Totaro Imasaka
      A sample containing nitrated aromatic hydrocarbons (NPAHs) was injected into the sample inlet port of a gas chromatograph (GC), along with hydrazine, a reducing reagent. The analytes that eluted from the GC column were measured by mass spectrometry (MS) using an ultraviolet femtosecond laser as the ionization source. When no reducing reagent was used, large numbers of polycyclic aromatic hydrocarbons (PAHs) including NPAHs were observed in the two-dimensional GC/MS display. In contrast, when hydrazine was present, reduced forms of NPAHs, which included amino PAHs, were detected. When a palladium or platinum catalyst was placed in the GC inlet port, the compounds were further reduced to non-aromatic hydrocarbons. The present approach would be useful for studies to evaluate the chemical reaction that converts the constituents contained in exhaust emitted from a diesel engine.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.09.049
      Issue No: Vol. 996 (2017)
       
  • Smartphone based non-invasive salivary glucose biosensor
    • Authors: Anuradha Soni; Sandeep Kumar Jha
      Pages: 54 - 63
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Anuradha Soni, Sandeep Kumar Jha
      The present work deals with the development of a non-invasive optical glucose biosensor using saliva samples and a smartphone. The sensor was fabricated with a simple methodology by immobilization of Glucose oxidase enzyme along with a pH responsive dye on a filter paper based strip. The strip changes color upon reaction with glucose present in saliva and the color changes were detected using a smartphone camera through RGB profiling. This standalone biosensor showed good sensitivity and low interference while operating within 20 s response time. We used various means for improvements such as the use of slope method instead of differential response; use of a responsive pH indicator and made numerous tweaks in the smartphone app. Calibration with spiked saliva samples with slopes for (R + G + B) pixels revealed an exponentially increasing calibration curve with a linear detection range of 50–540 mg/dL, sensitivity of 0.0012 pixels sec−1/mg dL−1 and LOD of 24.6 mg/dL. The biosensor was clinically validated on both healthy and diabetic subjects divided into several categories based on sex, age, diabetic status etc. and correlation between blood and salivary glucose has been established for better standardization of the sensor. Correlation of 0.44 was obtained between blood and salivary glucose in healthy individuals whereas it was 0.64 and 0.94 in case of prediabetic and diabetic patients respectively. The developed biosensor has the potential to be used for mass diagnosis of diabetes especially in such areas where people remain prohibited from routine analysis due to high healthcare cost. Apart from that, a smartphone would be the only device the user needs for this measurement, along with a disposable low cost test strip.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.003
      Issue No: Vol. 996 (2017)
       
  • Simultaneous detection of folic acid and methotrexate by an optical sensor
           based on molecularly imprinted polymers on dual-color CdTe quantum dots
    • Authors: Ali A. Ensafi; Parisa Nasr-Esfahani; B. Rezaei
      Pages: 64 - 73
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Ali A. Ensafi, Parisa Nasr-Esfahani, B. Rezaei
      In this work, molecularly imprinted polymers (MIPs) were used on the surface of cadmium telluride quantum dots (CdTe QDs) for the simultaneous determination of folic acid (FA) and methotrexate (MTX). For this purpose, two different sizes of CdTe QDs with emission peaks in the yellow (QDY) and orange (QDO) spectral regions were initially synthesized and capped with MIPs. FA and MTX were used as templates for the synthesis of the two composites and designated as QDY-MIPs and QDO-MIPs, respectively. Fourier transform infrared spectroscopy, transmission electron microscopy, and fluorescence spectroscopy were employed to characterize the composites. QDY-MIPs and QDO-MIPs were then mixed (to form QDs-MIPs) and excited at identical excitation wavelengths; they emitted two different emission wavelengths without any spectral overlap. The fluorescence signals of QDY-MIPs and QDO-MIPs diminished in intensity with increasing concentration of the corresponding template molecules. Under optimal conditions, the dynamic range was 0.5–20 μmol L−1 for FA and MTX, and the detection limits for FA and MTX were 32.0 nmol L−1 and 34.0 nmol L−1, respectively. The reproducibility of the method was checked for 12.5 μmol L−1 of FA and MTX to find RSD values of 4.2% and 6.3%, respectively. Finally, the applicability of the method was checked using human blood plasma samples. Results indicated the successful application of the method as a fluorescent probe for the rapid and simultaneous detection of FA and MTX in real samples.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.011
      Issue No: Vol. 996 (2017)
       
  • Loop-mediated isothermal amplification using self-avoiding molecular
           recognition systems and antarctic thermal sensitive uracil-DNA-glycosylase
           for detection of nucleic acid with prevention of carryover contamination
    • Authors: Yi Wang; Dongxin Liu; Jianping Deng; Yan Wang; Jianguo Xu; Changyun Ye
      Pages: 74 - 87
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Yi Wang, Dongxin Liu, Jianping Deng, Yan Wang, Jianguo Xu, Changyun Ye
      Loop-mediated isothermal amplification (LAMP) is the most popular technique to amplify nucleic acid sequence without the use of temperature cycling. However, LAMP is often confounded by false-positive results, arising from interactions between (hetero-dimer) or within (self-dimerization) primers, off-target hybrids and carryover contaminants. Here, we devised a new LAMP technique that is self-avoiding molecular recognition system (SAMRS) components and antarctic thermal sensitive uracil-DNA-glycosylase (AUDG) enzyme-assisted, termed AUDG-SAMRS-LAMP. Incorporating SAMRS components into 3′-ends of LAMP primers can improve assay's specificity, which completely prevents the non-specific amplification yielding from off-target hybrids and undesired interactions between or within primers. Adding AUDG into reaction mixtures can effectively eliminate the false-positive results arising from carryover contamination, thus the genuine positive reactions are generated from the amplification of target templates. Furthermore, AUDG-SAMRS-LAMP results are confirmed using a new analysis strategy, which is developed for detecting LAMP amplicons by lateral flow biosensor (LFB). Only a single labeled primer is required in the analysis system, thus the false positive results arising from hybridization (the labeled primer and probe, or between two labeled primers) are avoided. Hence, the SAMRS components, AUDG and LFB convert traditional LAMP from a technique suited for the research laboratory into one that has practical value in the field of diagnosis. Human Tuberculosis (TB) is caused by infection with members of Mycobacterium tuberculosis complex (MTC), which are detected by the AUDG-SAMRS-LAMP technique to demonstrate the availability of target analysis. The proof-of-concept method can be reconfigured to detect various nucleic acids by redesigning the specific primers.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.022
      Issue No: Vol. 996 (2017)
       
  • Novel free-radical mediated lipid peroxidation biomarkers in newborn
           plasma
    • Authors: Ángel Sánchez-Illana; Sudhin Thayyil; Paolo Montaldo; Dorothea Jenkins; Guillermo Quintás; Camille Oger; Jean-Marie Galano; Claire Vigor; Thierry Durand; Máximo Vento; Julia Kuligowski
      Pages: 88 - 97
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Ángel Sánchez-Illana, Sudhin Thayyil, Paolo Montaldo, Dorothea Jenkins, Guillermo Quintás, Camille Oger, Jean-Marie Galano, Claire Vigor, Thierry Durand, Máximo Vento, Julia Kuligowski
      Oxidative stress derived from perinatal asphyxia appears to be closely linked to neonatal brain damage and lipid peroxidation biomarkers have shown to provide predictive power of oxidative stress related pathologies in situations of hypoxia and reoxygenation in the newborn. The objective of this work was to develop and validate of a comprehensive liquid chromatography tandem mass spectrometry approach for the quantitative profiling of 28 isoprostanoids in newborn plasma samples covering a broad range of lipid peroxidation product classes. The method was developed taking into account the specific requirements for its use in neonatology (i.e. limited sample volumes, straightforward sample processing and high analytical throughput). The method was validated following stringent FDA guidelines and was then applied to the analysis of 150 plasma samples collected from newborns. Information obtained from the quantitative analysis of isoprostanoids was critically compared to that provided by a previously developed approach aiming at the semi-quantitative detection of total parameters of fatty acid derived lipid peroxidation biomarkers.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.09.026
      Issue No: Vol. 996 (2017)
       
  • Hydrophilic interaction liquid chromatography of hydroxy aromatic
           carboxylic acid positional isomers
    • Authors: Ashley E. Richardson; Neil D. Danielson
      Pages: 98 - 105
      Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996
      Author(s): Ashley E. Richardson, Neil D. Danielson
      Hydrophilic interaction liquid chromatography (HILIC) has become increasingly popular as an alternative to reversed phase LC due to its ease of separating complex polar compound mixtures and the compatibility of the mobile phase with mass spectrometry (MS). Using a plain silica column (150  mm × 4.6  mm), we have shown a mixture containing three hydroxybenzoic acid isomers plus syringic and vanillic acid and three hydroxycinnamic acid isomers plus ferulic and sinapic acid can be separated using a mobile phase comprised of 90% acetonitrile (MeCN) and 10% 20 mM ammonium acetate at pH 6 in under 45 min. This method is appropriate when using UV detection at 275 nm. However, for improved MS compatibility, a buffer concentration of 10 mM is recommended but this greatly decreases the analyte retention factors. A second more nonpolar organic solvent component in the mobile phase (particularly pentane which has not been previously considered for HILIC) is found to offset this loss in retention. The optimum mobile phase is found to be 90% MeCN, 5% 10 mM ammonium acetate pH 6, and 5% pentane with resolution of eight of the ten compounds with a separation time of 30 min. Using UV detection, we have shown that detection limits range from 36 to 133 pmole and quantitation limits are spread from 94 to 376 pmole for six of the analytes. Upon testing this method on two other silica columns from different manufacturers, it is found that while resolution is similar, further optimization of the mobile phase is recommended.
      Graphical abstract image

      PubDate: 2017-11-16T02:38:23Z
      DOI: 10.1016/j.aca.2017.10.001
      Issue No: Vol. 996 (2017)
       
  • Development and application of mass spectrometric techniques for
           ultra-trace determination of 236U in environmental samples-A review
    • Authors: Wenting Bu; Jian Zheng; Michael E. Ketterer; Sheng Hu; Shigeo Uchida; Xiaolin Wang
      Pages: 1 - 20
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Wenting Bu, Jian Zheng, Michael E. Ketterer, Sheng Hu, Shigeo Uchida, Xiaolin Wang
      Measurements of the long-lived radionuclide 236U are an important endeavor, not only in nuclear safeguards work, but also in terms of using this emerging nuclide as a tracer in chemical oceanography, hydrology, and actinide sourcing. Depending on the properties of a sample and its neutron irradiation history, 236U/238U ratios from different sources vary significantly. Therefore, this ratio can be treated as an important fingerprint for radioactive source identification, and in particular, affords a definitive means of discriminating between naturally occurring U and specific types of anthropogenic U. The development of mass spectrometric techniques makes it possible to determine ultra-trace levels of 236U in environmental samples. In this paper, we review the current status of mass spectrometric approaches for determination of 236U in environmental samples. Various sample preparation methods are summarized and compared. The mass spectrometric techniques emphasized herein are thermal ionization mass spectrometry (TIMS), inductively coupled plasma mass spectrometry (ICP-MS) and accelerator mass spectrometry (AMS). The strategies or principles used by each technique for the analysis of 236U are described. The performances of these techniques in terms of abundance sensitivity and detection limit are discussed in detail. To date, AMS exhibits the best capability for ultra-trace determinations of 236U. The levels and behaviors of 236U in various environmental media are summarized and discussed as well. Results suggest that 236U has an important, emerging role as a tracer for geochemical studies.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.029
      Issue No: Vol. 995 (2017)
       
  • Optimization of GC/TOF MS analysis conditions for assessing host-gut
           microbiota metabolic interactions: Chinese rhubarb alters fecal aromatic
           amino acids and phenol metabolism
    • Authors: Shan Yin; Pan Guo; Dafu Hai; Li Xu; Jiale Shu; Wenjin Zhang; Muhammad Idrees Khan; Irwin J. Kurland; Yunping Qiu; Yumin Liu
      Pages: 21 - 33
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Shan Yin, Pan Guo, Dafu Hai, Li Xu, Jiale Shu, Wenjin Zhang, Muhammad Idrees Khan, Irwin J. Kurland, Yunping Qiu, Yumin Liu
      In this paper, an optimized method based on gas chromatography/time-of-flight mass spectrometry (GC-TOFMS) platform has been developed for the analysis of gut microbial-host related co-metabolites in fecal samples. The optimization was performed with proportion of chloroform (C), methanol (M) and water (W) for the extraction of specific metabolic pathways of interest. Loading Bi-plots from the PLS regression model revealed that high concentration of chloroform emphasized the extraction of short chain fatty acids and TCA intermediates, while the higher concentration of methanol emphasized indole and phenyl derivatives. Low level of organic solution emphasized some TCA intermediates but not for indole and phenyl species. The highest sum of the peak area and the distribution of metabolites corresponded to the extraction of methanol/chloroform/water of 225:75:300 (v/v/v), which was then selected for method validation and utilized in our application. Excellent linearity was obtained with 62 reference standards representing different classes of gut microbial-host related co-metabolites, with correlation coefficients (r 2) higher than 0.99. Limit of detections (LODs) and limit of qualifications (LOQs) for these standards were below 0.9 nmol and 1.6 nmol, respectively. The reproducibility and repeatability of the majority of tested metabolites in fecal samples were observed with RSDs lower than 15%. Chinese rhubarb-treated rats had elevated indole and phenyl species, and decreased levels of polyamine such as putrescine, and several amino acids. Our optimized method has revealed host-microbe relationships of potential importance for intestinal microbial metabolite receptors such as pregnane X receptor (PXR) and aryl hydrocarbon receptor (AHR) activity, and for enzymes such as ornithine decarboxylase (ODC).
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.042
      Issue No: Vol. 995 (2017)
       
  • Fast probing of glucose and fructose in plant tissues via plasmonic
           
    • Authors: Pir Muhammad; Jia Liu; Rongrong Xing; Yanrong Wen; Yijia Wang; Zhen Liu
      Pages: 34 - 42
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Pir Muhammad, Jia Liu, Rongrong Xing, Yanrong Wen, Yijia Wang, Zhen Liu
      Determination of specific target compounds in agriculture food and natural plant products is essential for many purposes; however, it is often challenging due to the complexity of the sample matrices. Herein we present a new approach called plasmonic affinity sandwich assay for the facile and rapid probing of glucose and fructose in plant tissues. The approach mainly relies on molecularly imprinted plasmonic extraction microprobes, which were prepared on gold-coated acupuncture needles via boronate affinity controllable oriented surface imprinting with the target monosaccharide as the template molecules. An extraction microprobe was inserted into plant tissues under investigation, which allowed for the specific extraction of glucose or fructose from the tissues. The glucose or fructose molecules extracted on the microprobe were labeled with boronic acid-functionalized Raman-active silver nanoparticles, and thus affinity sandwich complexes were formed on the microprobes. After excess Raman nanotags were washed away, the microprobe was subjected to Raman detection. Upon being irradiated with a laser beam, surface plasmon on the gold-coated microprobes was generated, which further produced plasmon-enhanced Raman scattering of the silver-based nanotags and thereby provided sensitive detection. Apple fruits, which contain abundant glucose and fructose, were used as a model of plant tissues. The approach exhibited high specificity, good sensitivity (limit of detection, 1 μg mL−1), and fast speed (the whole procedure required only 20 min). The spatial distribution profiles of glucose and fructose within an apple were investigated by the developed approach.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.044
      Issue No: Vol. 995 (2017)
       
  • Photometric flow analysis system for biomedical investigations of
           iron/transferrin speciation in human serum
    • Authors: Kamil Strzelak; Natalia Rybkowska; Agnieszka Wiśniewska; Robert Koncki
      Pages: 43 - 51
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Kamil Strzelak, Natalia Rybkowska, Agnieszka Wiśniewska, Robert Koncki
      The Multicommutated Flow Analysis (MCFA) system for the estimation of clinical iron parameters: Serum Iron (SI), Unsaturated Iron Binding Capacity (UIBC) and Total Iron Binding Capacity (TIBC) has been proposed. The developed MCFA system based on simple photometric detection of iron with chromogenic agent (ferrozine) enables a speciation of transferrin (determination of free and Fe-bound protein) in human serum. The construction of manifold was adapted to the requirements of measurements under changing conditions. In the course of studies, a different effect of proteins on SI and UIBC determination has been proven. That was in turn the reason to perform two kinds of calibration methods. For measurements in acidic medium for SI/holotransferrin determination, the calibration curve method was applied, characterized by limit of determination and limit of quantitation on the level of 3.4 μmol L−1 and 9.1 μmol L−1, respectively. The determination method for UIBC parameter (related to apotransferrin level) in physiological medium of pH 7.4 forced the use of standard addition method due to the strong influence of proteins on obtaining analytical signals. These two different methodologies, performed in the presented system, enabled the estimation of all three clinical iron/transferrin parameters in human serum samples. TIBC corresponding to total transferrin level was calculated as a sum of SI and UIBC.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.10.015
      Issue No: Vol. 995 (2017)
       
  • Identification of new tetrahydroxylated metabolites of Polycyclic Aromatic
           Hydrocarbons in hair as biomarkers of exposure and signature of DNA adduct
           levels
    • Authors: Nathalie Grova; Jean-Philippe Antignac; Emilie M. Hardy; Fabrice Monteau; Karine Pouponneau; Bruno Le Bizec; Brice M.R. Appenzeller
      Pages: 65 - 76
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Nathalie Grova, Jean-Philippe Antignac, Emilie M. Hardy, Fabrice Monteau, Karine Pouponneau, Bruno Le Bizec, Brice M.R. Appenzeller
      The present study addresses the hypothesis that the concentration of tetrahydroxylated Polycylic Aromatic Hydrocarbons (tetra-OH-PAHs) in hair might be a useful biomarker of human exposure to PAHs, providing quantitative assessment of the internal dose, as well as information on the associated toxicity in relation to individual's specific metabolism. By means of animal models, this work aimed at identifying new tetra-OH-PAHs which can be released from the hydrolysis of DNA-adducts and can also be directly detected in biological matrices usually used in the field of biomonitoring such as hair and urine. Results obtained from a targeted gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) approach, demonstrated the presence of 8 tetrahydroxylated metabolites in DNA and 23 in hairs of rats exposed to mixtures of PAHs, which had never been analyzed before. Ten tetra-OH-PAHs were clearly characterized by using their analytical standards, corresponding to 4 parent PAHs (phenanthrene, chrysene, benz[a]anthracene and benzo[a]pyrene) whereas 13 tetra-OH-PAHs from 3 other parents (anthracene, fluoranthene and benz[k]fluoranthene) were detected but not yet characterized. No tetrahydroxylated metabolite has been clearly identified for naphthalene, fluorene, benzo[b]fluoranthene, benzo[g,h,i]perylene, or dibenzo[a,h]anthracene, which can all potentially form adducts. The relevance of tetra-OH-PAH analysis in hair as biomarkers of PAH exposure was evaluated in a dose-response study conducted on 64 rats (Long Evans females/n = 8 per groups) under repeated exposure (3 times per week) to a mixture of 16 PAHs at low doses (0.01–0.8 mg/kg) for 90 days. Most of the tetra-OH-PAHs targeted in the method were detected in the hairs of the rats, regardless of the dose of exposure. Significant linear relationships (R2 ranging from 0.558 to 0.964, p < 0.001) were observed between the administered dose and the tetra-OH-PAH concentrations in the hairs for 20 out of the 23 metabolites. By widening the range of PAH metabolites used as biomarkers of exposure so as to include the analysis of PAH tetrahydroxylated forms (especially those exhibiting more than 5 aromatic rings), the present methodology will enable multi-exposure assessments which are more accurately representative of actual situations of exposure to PAHs.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.10.002
      Issue No: Vol. 995 (2017)
       
  • Multi-parametric polymer-based potentiometric analytical microsystem for
           future manned space missions
    • Authors: Antonio Calvo-López; Mar Puyol; Joan Manel Casalta; Julián Alonso-Chamarro
      Pages: 77 - 84
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Antonio Calvo-López, Mar Puyol, Joan Manel Casalta, Julián Alonso-Chamarro
      The construction and evaluation of a Cyclic Olefin Copolymer (COC)-based continuous flow potentiometric microanalyzer to simultaneously monitor potassium, chloride and nitrate ions in samples from an on-board water recycling process expected to be installed in future manned space missions is presented. The main goals accomplished in this work address the specific required characteristics for a miniaturized on-line monitoring system to control water quality in such missions. To begin with, the integration of three ion-selective electrodes (ISEs) and a reference electrode in a compact microfluidic platform that incorporates a simple automatic autocalibration process allows obtaining information about the concentration of the three ions with optimal analytical response characteristics, but moreover with low reagents consumption and therefore with few waste generation, which is critical for this specific application. By a simple signal processing (signal removal) the chloride ion interference on the nitrate electrode response can be eliminated. Furthermore, all fluidics management is performed by computer-controlled microvalves and micropumps, so no manual intervention of the crew is necessary. The analytical features provided by the microsystem after the optimization process were a linear range from 6.3 to 630 mg L−1 and a detection limit of 0.51 mg L−1 for the potassium electrode, a linear range from 10 to 1000 mg L−1 and a detection limit of 1.58 mg L−1 for the chloride electrode and a linear range from 10 to 1000 mg L−1 and a detection limit of 3.37 mg L−1 for the nitrate electrode with a reproducibility (RSD) of 4%, 2% and 3% respectively. Sample throughput was 12 h−1 with a reagent consumptions lower than 2 mL per analysis.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.08.043
      Issue No: Vol. 995 (2017)
       
  • Performance of electrokinetic stacking enhanced paper-based analytical
           device with smartphone for fast detection of fluorescent whitening agent
    • Authors: Yi-Zhen Song; Xiu-Xiu Zhang; Biao Ma; Zhi-Yong Wu; Zi-Qiang Zhang
      Pages: 85 - 90
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Yi-Zhen Song, Xiu-Xiu Zhang, Biao Ma, Zhi-Yong Wu, Zi-Qiang Zhang
      Quantification is a fundamental aspect of performance of an analytical system. Paper-based analytical device (PAD) as an on-site detection platform has drawn wide attention mainly due to its portability and cost effectiveness. In this work, a portable and low-cost PAD for online preconcentration and sensitive determination of fluorescent whitening agent (FWA) was demonstrated, which was consisted of ultra violet light-emitting diode (UV LED), macro-focusing lens, smartphone and miniaturized DC voltage source. Taking a widely used FWA component VBL as the analyte, the performance of the PAD enhanced with electrokinetic stacking (ES) and fluorescence imaging detection was systematically investigated. With ES, the sensitivity of the PAD system was 160-fold enhanced, and a limit of detection (LOD) of 0.06 μg mL−1 was achieved. The dynamic range was 0.1–10.0 μg mL−1 (linear in 0.1–0.7 μg mL−1, R2 = 0.99). With manual operation, the relative standard deviation (RSD) of intra-day and inter-day were all below 15%. Eventually, VBL from different napkin samples and toilet paper was determined with average recovery rates in the range of 90%–95% (RSD = 8.0%–12.0%). This work shows that with ES, the sensitivity of PAD can be greatly improved, and a LOD close to a desktop fluorescent spectrophotometer can be achieved as demonstrated by the detection of FWA component.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.040
      Issue No: Vol. 995 (2017)
       
  • A highly sensitive fluorescent turn-on biosensor for glycoproteins based
           on boronic acid functional polymer capped Mn-doped ZnS quantum dots
    • Authors: Lifang Chang; Haocheng Wu; Xiwen He; Langxing Chen; Yukui Zhang
      Pages: 91 - 98
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Lifang Chang, Haocheng Wu, Xiwen He, Langxing Chen, Yukui Zhang
      A simple fluorescence turn-on sensor has been designed for the highly sensitive detection of glycoproteins on the basis of boronic acid functional polymer capped Mn-doped ZnS quantum dots (QDs@MPS@AAPBA). In the absence of glycoproteins, the fluorescence emission intensity of the QDs@MPS@AAPBA was relatively weaker due to the effective electronic transfer from the QDs to the boron moieties on its surface. While the glycoproteins were introduced into the system, an obvious fluorescence enhancement was observed. It was attributed to the boron moieties covalent binding glycans of the glycoproteins resulting in the electronic transfer process being inhibited. Under the optimal conditions, this fluorescent probe not only could be applied in a wide pH range of 5.0–9.0, but also the binding constants and detection limits of the QDs@MPS@AAPBA for horseradish peroxidase (HRP) and transferrin (TRF) were up to 7.23 × 106 M−1, 1.53 × 107 M−1 and 1.44 × 10−10 M, 3.36 × 10−10 M, respectively. Finally, this proposed method has also been utilized for the TRF determination in serum without any complicated pretreatment and the recovery was in the range of 95.7%–103.0%. As a result, it is promising for application on the glycoproteins detection in complex biological samples.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.037
      Issue No: Vol. 995 (2017)
       
  • Functionalized carbon quantum dots with dopamine for tyrosinase activity
           analysis
    • Authors: Jin-Jie Hu; Xiao-Lin Bai; Yi-Ming Liu; Xun Liao
      Pages: 99 - 105
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Jin-Jie Hu, Xiao-Lin Bai, Yi-Ming Liu, Xun Liao
      Tyrosinase (TYR) is a key enzyme in melanin biosynthesis and its activity is an important biomarker for dermatological disorders, such as vitiligo, melanoma and actinic damages. Sensitive assay for TYR activity is significant for basic and clinical research. In this work, a facile fluorescent assay for TYR activity based on dopamine functionalized carbon quantum dots (CQDs-Dopa) has been developed. Dopamine (Dopa) was covalently bond to CQDs through a simple one-pot hydrothermal method, and the prepared CQDs-Dopa exhibited a fluorescence emission at 499 nm under exciting wavelength at 310 nm with a quantum yield of approximately 2.1%. When TYR was mixed with CODs-Dopa, the dopamine moiety in CQDs-Dopa conjugate was oxidized to O-dopaquinone, and an intra-particle photo-induced electron transfer (PET) process consequently occurred between CQDs and O-dopaquinone to quench the fluorescence of CQDs-Dopa. TYR activity can be determined based on the fluorescence quenching degree of CQDs-Dopa. This assay covered two broad linear ranges: 44.4–711.1 U L−1 and 711.1–2925.4 U L−1, with detection limit of 17.7 U L−1. The proposed fluorescent assay was applied to TYR activity measurement in human serum samples. It showed promising potential for TYR activity assay in clinical applications.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.038
      Issue No: Vol. 995 (2017)
       
  • High throughput human plasma N-glycan analysis using DNA analyzer and
           multivariate analysis for biomarker discovery
    • Authors: Hua-tao Feng; Siying Lim; Anna Karen Carrasco Laserna; Pingjing Li; Xuejiao Yin; Erhan Simsek; Shaheer H. Khan; Shiaw-Min Chen; Sam F.Y. Li
      Pages: 106 - 113
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Hua-tao Feng, Siying Lim, Anna Karen Carrasco Laserna, Pingjing Li, Xuejiao Yin, Erhan Simsek, Shaheer H. Khan, Shiaw-Min Chen, Sam F.Y. Li
      Carbohydrates form the majority of organic compounds found in nature and their presence on proteins influences many important bioactivities. Therefore, glycan profiling shows potential in clinical applications. This work demonstrates the use of a high-throughput GlycanAssure™ sample preparation technology and multi-capillary DNA analyzer for the analysis of the major N-linked glycans (N-glycans) found in human plasma. The application involves two biomarker studies: (1) in profiling patients with chronic kidney disease and (2) in differentiating heart disease patients with normal controls in response to an antiplatelet drug from hypo-responders. Due to complexity of the study data, bio-statistical methods were applied to data processing. 37 N-glycan peaks were observed from separation results, with confirmed structure for most glycans. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to build models to differentiate the patient groups. The percentages of correct classification of the models reached 95.45% for the chronic kidney disease dataset and 85.42% for the anti-platelet drug response dataset. Given that blood N-glycan profiles had been shown to reflect certain disease states, this high-throughput platform could potentially be used for the simultaneous screening of multiple glycan biomarkers, with as little as one drop of blood sample.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.003
      Issue No: Vol. 995 (2017)
       
  • Integration of capillary electrophoresis with gold nanoparticle-based
           colorimetry
    • Authors: Tong Li; Zhenglong Wu; Weidong Qin
      Pages: 114 - 121
      Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995
      Author(s): Tong Li, Zhenglong Wu, Weidong Qin
      A method integrating capillary electrophoresis (CE) and gold nanoparticle aggregation-based colorimetry (AuNP-ABC) was described. By using a dual-sheath interface, the running buffer was isolated from the colorimetric reaction solution so that CE and AuNP-ABC would not interfere with each other. The proof-of-concept was validated by assay of polyamidoamine (PAMAM) dendrimers that were fortified in human urine samples. The factors influencing the CE-AuNP-ABC performances were investigated and optimized. Under the optimal conditions, the dendrimers were separated within 8 min, with detection limits of 0.5, 1.2 and 2.6 μg mL−1 for PAMAM G1.0, G2.0 and G3.0, respectively. The sensitivity of CE-AuNP-ABC was comparable to or even better than those of liquid chromatography-fluorimetry and liquid chromatography-mass spectrometry. The results suggested that the proposed strategy can be applied to facile and quick determination of analytes of similar properties in complex matrices.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.014
      Issue No: Vol. 995 (2017)
       
  • A cell surface specific two-photon fluorescent probe for monitoring
           intercellular transmission of hydrogen sulfide
    • Authors: Yu-Jia Fu; Hui-Wen Yao; Xiao-Yan Zhu; Xiao-Feng Guo; Hong Wang
      Pages: 1 - 9
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Yu-Jia Fu, Hui-Wen Yao, Xiao-Yan Zhu, Xiao-Feng Guo, Hong Wang
      Hydrogen sulfide (H2S) is a new endogenously generated gasotransmitter and has implicated in many physiologies and pathologies closely related to its intracellular and intercellular signaling transduction. Although many fluorescent probes have been exploited to track and quantify H2S in living systems, none of them could be used for monitoring intercellular transmission of H2S. Herein, we developed a cell surface specific H2S probe, 4-azido-6-sulfo-N-hexadecyl-1,8-naphthalimide, sodium salt (ASNHN-N3), trying to investigate the behaviors of extracellular release of H2S. ASNHN-N3 is week fluorescent and could react with H2S at 37 °C in pH 7.4 buffer solutions to form product ASNHN-NH2 with strong fluorescence (Φ = 0.22). Using ASNHN-N3 as H2S probe, excellent linear correlation versus the concentration of NaHS was obtained ranging from 0 to 10 μM and the detection limit was 0.75 μM. With the lipid anchor and the hydrophilic sulfonic group introduced into the 1,8-naphthalimide (a skeleton of two-photon fluorescent probe), the amphiphilic probe is located at the surface of living cells which can record H2S efflux from the cell diffusing across the plasma membrane in living cells and deep-tissue by using two-photon microscopy. Thus we present a new strategy for further studying the mechanism of signaling molecules in cell communication and signal pathways.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.030
      Issue No: Vol. 994 (2017)
       
  • Direct Electrochemical DNA Sensor based on a new redox oligomer modified
           with ferrocene and carboxylic acid: Application to the detection of
           Mycobacterium tuberculosis mutant strain
    • Authors: Salma Bizid; Saber Blili; Rym Mlika; Ayoub Haj Said; Hafsa Korri-Youssoufi
      Pages: 10 - 18
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Salma Bizid, Saber Blili, Rym Mlika, Ayoub Haj Said, Hafsa Korri-Youssoufi
      A new redox oligomer “oligo-methoxy-phenyl-acetonitrile” (Fc-acid-OMPA) modified with ferrocene groups and carboxylic acids as functional groups in side chains, has been synthesized. The redox indicator has been used for monitoring the electrochemical behavior. The functional groups give the flexibility for direct covalent attachment of biomolecules. The electrochemical properties of the redox oligomer film deposited on gold electrodes have been studied by cyclic voltammetry (CV), which showed a rate of electron transfer of 6.43 s−1. The oligomer has been studied as a transducer for electrochemical DNA sensing and for this purpose the acid functional group of Fc-acid-OMPA was attached with the DNA probe of hepatitis C bearing amino group in 5′ position through amid link. The efficiency of DNA attachment on the oligomer film has been analyzed by X-Ray Photoelectron Spectrometry (XPS) and FT-IR spectroscopy. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) have been used to analyze the biosensor construction and DNA detection. A wide linear range of detection from 1 fM to 100 pM have been demonstrated with a limit of detection (LOD) of 0.2 fM. The biosensor has showed an appreciated sensitivity to PCR samples of genomic DNA from Mycobacterium tuberculosis, and has been able to detect a single mutation which confers resistance of M. tuberculosis to rifampicin drug.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.022
      Issue No: Vol. 994 (2017)
       
  • Facile synthesis of magnetic metal organic frameworks for highly efficient
           proteolytic digestion used in mass spectrometry-based proteomics
    • Authors: Rui Zhai; Yifeng Yuan; Fenglong Jiao; Feiran Hao; Xiang Fang; Yangjun Zhang; Xiaohong Qian
      Pages: 19 - 28
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Rui Zhai, Yifeng Yuan, Fenglong Jiao, Feiran Hao, Xiang Fang, Yangjun Zhang, Xiaohong Qian
      Mass spectrometry (MS) based bottom-up strategy is now the first choice for proteomics analysis. In this process, highly efficient and complete enzymatic degradation of protein samples is extremely important to achieve in-depth protein coverage and high-throughput protein profiling. However, conventional in-solution digestion suffer from long digestion time and enzyme autolysis that limit the protein sample processing throughput and identification accuracy. Here, we developed a novel type of magnetic metal organic frameworks (MOFs)-based immobilized enzyme reactor, Fe3O4@DOTA-ZIF-90-trypsin. By introducing a stable chelator, 1,4,7,10-tetraazacyclododecane N,N′,N″,N‴-tetraacetic acid (DOTA), onto the magnetic cores, the hybrid supporting matrix of the immobilized enzyme reactor Fe3O4@DOTA-ZIF-90 has novel characteristics that include: i) favourable magnetic response (1.01 emu g−1) that makes the operation easy and convenient, ii) ultrahigh surface area (565.21 m2 g-11) and active sites that ensure high loading amounts and covalent linkage of enzyme, and iii) excellent structural and thermal stability that endows the immobilized enzyme reactor a prolonged lifespan. The performance of the magnetic MOFs-immobilized trypsin is first investigated using the standard protein, BSA, and the results showed that the immobilized enzyme reactor exhibits satisfactory digestion efficiency within only 1 min with the sequence coverage (80%) that is comparable or even better than that (70%) of the traditional 12 h-free trypsin digestion. To test the applicability of the magnetic MOFs-based immobilized enzyme reactor, protein samples extracted from 400 oocytes in mice were digested through the new immobilized enzyme reactor. In total, 8957 peptides corresponding to 1843 protein groups are identified, which are nearly of 40% and 67% increases in the number of identified proteins and peptides compared to using in-solution digestion with free proteases. Specifically, the identification of oocyte-specific proteins was critical in the discovery of and understanding the regulation mechanism of oocyte maturation. Thus, this synthetic procedure of Fe3O4@DOTA-ZIF-90 provides a universal method for fabrication of magnetic MOFs materials, and the successful application of Fe3O4@DOTA-ZIF-90-trypsin in efficient protein digestion for deeper proteome coverage will undoubtedly enlarge the uses for MOFs.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.08.048
      Issue No: Vol. 994 (2017)
       
  • Graphene grown on stainless steel mesh as a highly efficient sorbent for
           sorptive microextraction of polycyclic aromatic hydrocarbons from water
           samples
    • Authors: Amirhassan Amiri; Ferial Ghaemi
      Pages: 29 - 37
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Amirhassan Amiri, Ferial Ghaemi
      In this study, graphene grown on stainless steel mesh efficiently incorporates the advanced properties of graphene in the form of an ultra-thin coating with the open geometry of the substrate, resulting in a highly sensitive and fast sorptive device capable of extracting target analytes directly from sample matrices. The synthesis of graphene on the stainless steel mesh was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The advantages of the new microextraction device have been investigated for the determination of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples in combination with gas chromatography–flame ionization detector (GC–FID). The factors affecting the extraction efficiency such as stirring speed, extraction time, ionic strength and desorption conditions, were investigated and the optimal extraction conditions were established. Under the optimal extraction condition, linearity was in the range of 0.003–100 ng mL−1 with a correlation coefficient of 0.9923–0.9985. The limits of detection (LODs) of the developed method are obtained between 1 and 3 pg mL−1. The repeatability was assessed at two concentration levels (0.01 and 10 ng mL−1) and the relative standard deviations (RSDs) obtained were 4.9–8.7%. The preparation reproducibility of sorbent device, evaluated with the RSDs, was in the range of 7.3–10.2% (n = 5) in one batch, and 8.3–11.0% (n = 5) among different batches. Finally, the proposed method is applied for the determination of the target PAHs in the real water samples.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.08.049
      Issue No: Vol. 994 (2017)
       
  • Rapid fingerprinting of lignin by ambient ionization high resolution mass
           spectrometry and simplified data mining
    • Authors: Elizabeth A. Crawford; Stefanie Gerbig; Bernhard Spengler; Dietrich A. Volmer
      Pages: 38 - 48
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Elizabeth A. Crawford, Stefanie Gerbig, Bernhard Spengler, Dietrich A. Volmer
      Ambient ionization techniques are typically used to analyze samples in their native states with minimal or no sample pretreatment prior to mass spectrometric (MS) analysis. Desorption electrospray ionization (DESI) and direct analysis in real time (DART) were systematically investigated in this work for direct solid analysis of depolymerized lignin samples, with the goal of rapidly fingerprinting these samples, to efficiently characterize the subunits of this renewable energy source. High resolution MS was required for enhanced selectivity in this study due to the inherent structural complexity of lignin. DESI provided results across a broader mass range (up to m/z 700) than DART and also ionized saturated compounds of low oxygen-to-carbon (O/C) ratios and low double bond equivalents (DBE). While DART detected the same core lignin monomeric and dimeric compounds as seen with DESI and electrospray ionization (ESI), results were restricted to a narrower mass range to m/z 500, due to thermal degradation and losses of methoxy groups. In contrast to DESI and ESI, the DART spectra were nearly void of saturated components. On a structural level, the core lignin compounds were visually fingerprinted and ionization method performances critically assessed by employing simplified Kendrick-based data mining approaches. A novel simplified data visualization approach was developed in this work based on modified Kendrick mass defect (KMD) filtering for lignin subunits and plotting the mass defect values against the degree of unsaturation. Direct visualization of monomeric, dimeric and trimeric lignin species was simplified by the KMD separation plots, easily allowing the core lignin compounds to be visually identified and compared. Modified KMD bases, namely methoxy and phenol bases, which represent monomer-specific lignin constituents, were successfully used to classify and group the complex mixture of lignin species. Further separation of methoxy-related lignin species was successfully achieved by employing the more specific phenolic KMD base.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.012
      Issue No: Vol. 994 (2017)
       
  • Enhancing carbohydrate ion yield by controlling crystalline structures in
           matrix-assisted laser desorption/ionization mass spectrometry
    • Authors: Hsun Lee; Yin-Hung Lai; Yu-Meng Ou; Chien-Wei Tsao; Ya-Jin Jheng; Shu-Yun Kuo; Huan-Tsung Chang; Yi-Sheng Wang
      Pages: 49 - 55
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Hsun Lee, Yin-Hung Lai, Yu-Meng Ou, Chien-Wei Tsao, Ya-Jin Jheng, Shu-Yun Kuo, Huan-Tsung Chang, Yi-Sheng Wang
      Carbohydrate analysis is challenging due to lack of sensitive detection and efficient separation methods. Although matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is a sensitive tool, the low ionization efficiency of carbohydrates makes mass analyses inefficient. This work systematically examines the correlation between MALDI-MS sensitivity and carbohydrate sample morphology. Depending on the properties of the matrix used, the morphology changes through sample recrystallization after drying or imposition of hydrodynamic flows during droplet drying. Observation shows that amorphous solids and finer crystals offer higher carbohydrate sensitivity and spatial homogeneity than larger crystals. Clear evidences of an inverse correlation between sensitivity and crystal size are obtained when various kinds of carbohydrates are mixed with different matrixes. Similar experiments on proteins and peptides showed a negative or negligible effect. The result serves as a general guideline for improving efficiency in routine carbohydrate analysis.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.024
      Issue No: Vol. 994 (2017)
       
  • High reliable and robust ultrathin-layer gold coating porous silver
           substrate via galvanic-free deposition for solid phase microextraction
           coupled with surface enhanced Raman spectroscopy
    • Authors: Weiwei Bian; Zhen Liu; Gang Lian; Le Wang; Qilong Wang; Jinhua Zhan
      Pages: 56 - 64
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Weiwei Bian, Zhen Liu, Gang Lian, Le Wang, Qilong Wang, Jinhua Zhan
      That intense demand for both high sensitivity and high reliability has been a key factor strengthening the surface enhanced Raman spectroscopy (SERS) in the analytical application, particular in the hyphenation with pre-concentration technique. Credible data acquisition and processing is very dependent on the stable and uniform performance of SERS-active substrate. Here, a reliable and uniform ultrathin-layer Au was proposed for protecting the porous Ag fiber (porous Ag@Au) and applied in the solid phase microextraction coupled with SERS. The Au layer was carefully deposited on porous Ag surface to form the uniform film by a galvanic-free displacement reaction. This coating endowed the substrate with high oxidation-resistance under heating and good durability in the atmosphere condition. The extraction and SERS performance of Nitrofurazone and Semicarbazide were investigated on this fiber, the bands at 1350 cm−1 and 1387 cm−1 were selected as the characteristic peaks for quantitative determination, respectively. This robust and sensitive substrate provide the high enhancement factor of 1.3 × 106 and low LOD of 5.1 ppb for the extraction and identification of Nitrofurazone compounds. Importantly, this work develops a versatile strategy for rapid detection of prohibited antibiotic and its marker residue in a complex matrix.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.004
      Issue No: Vol. 994 (2017)
       
  • Controlling the orientation of probe molecules on surface-enhanced Raman
           scattering substrates: A novel strategy to improve sensitivity
    • Authors: Chengbin Sun; Tingkun Chen; Weidong Ruan; Bing Zhao; Qian Cong
      Pages: 65 - 72
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Chengbin Sun, Tingkun Chen, Weidong Ruan, Bing Zhao, Qian Cong
      Typically, the surface-enhanced Raman scattering (SERS) technique is employed in precious metallic substrates with spontaneously adsorbed probing molecules to acquire signals. Preferred chemical conditions including aggregate status, hydrophilic/hydrophobic surroundings, and smart linkers were created to enable the detection of targets in very low concentrations (lower than 1.0 × 10−7 M). Although the sensitivity of SERS is applicable to certain areas, it is not satisfied in several cases that require obtaining good resolved signals involving extremely few surface molecules. Thus, further improvements in the sensitivity based on existing SERS techniques pose a challenge and is desirable for all aspects of analytical chemistry. In this study, a novel strategy was employed by constructing a molecular template (MT) on the SERS substrates with spontaneously adsorbed probe molecules to improve the detection sensitivity of probe molecules. The proposed MT-assisted SERS technique differed from previous methods as it provides a completely new method for improving the limit of detection (LOD) of SERS by controlling molecular orientations. The surface selection rules of SERS spectra were first introduced as an effective strategy to improve the detection sensitivity, and this was extremely beneficial with respect to analytical applications. The use of the MT-assisted SERS technique indicated that the LOD of probe molecules of p-aminobenzenethiol (8.0 × 10−9 M) and 4-mercaptobenzoic (1.0 × 10−7 M) acids on noble metallic substrates exhibited nearly one order of magnitudes. Hence, the proposed method paves a way to detect the molecules under improved sensitivity at extreme low concentrations. The study corresponded to a proof-of-concept study of MT-assisted SERS for SERS-based applications in ultra-sensitive analysis.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.10.004
      Issue No: Vol. 994 (2017)
       
  • A near-infrared fluorescent probe based on BODIPY derivative with high
           quantum yield for selective detection of exogenous and endogenous cysteine
           in biological samples
    • Authors: Song-Jiao Li; Ya-Jun Fu; Chun-Yan Li; Yong-Fei Li; Lan-Hua Yi; Juan Ou-Yang
      Pages: 73 - 81
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Song-Jiao Li, Ya-Jun Fu, Chun-Yan Li, Yong-Fei Li, Lan-Hua Yi, Juan Ou-Yang
      Cysteine (Cys) is involved in cellular growth and Cys deficiency is related with many diseases. So far, a number of fluorescent probes have been constructed for the detection of Cys successfully. However, the probes are difficult to discriminate Cys from Hcy and the emission wavelength of the probes is in ultraviolet or visible range. Herein, a NIR fluorescent probe named NIR-BODIPY-Ac is synthesized and used to detect Cys. The emission wavelength of the probe is at 708 nm that belongs to near-infrared (NIR) region by attaching indolium to BODIPY core, which is suitable for bioimaging in vivo. Moreover, the probe exhibits high fluorescence quantum yield (Φ = 0.51) after the addition of Cys and high sensitivity toward Cys with 81-fold fluorescence enhancement. The linear range of the probe for Cys covers from 0.2 to 30 μM with a detection limit of 0.05 μM. Furthermore, the probe shows high selectivity towards Cys owing to the fact that there is more fast reaction rate between the probe and Cys than that of Hcy. In particular, the NIR fluorescent probe is applied for the detection of exogenous and endogenous Cys in biological samples such as cell, tissue and mouse with satisfactory results.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.031
      Issue No: Vol. 994 (2017)
       
  • A novel visible-light driven photoelectrochemical immunosensor based on
           multi-amplification strategy for ultrasensitive detection of
           microcystin-LR
    • Authors: Jie Wei; Aori Qileng; Yun Yan; Hongtao Lei; Shengsen Zhang; Weipeng Liu; Yingju Liu
      Pages: 82 - 91
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Jie Wei, Aori Qileng, Yun Yan, Hongtao Lei, Shengsen Zhang, Weipeng Liu, Yingju Liu
      An ultrasensitive photoelectrochemical (PEC) immunoassay based on multiple signal amplification strategy was fabricated for the detection of microcystin-LR (MC-LR). The CdS/TiO2 nanorod arrays (CdS/TiO2 NRAs) modified FTO electrode, which can weaken the self-oxidation by photogenerated holes of CdS nanoparticles, and limit the recombination of electron-hole pairs and broaden optical absorption of TiO2 NRAs, was used as a visible-light driven material to immobilize antigens. Then, Fe3O4 nanoparticles/polydopamine (Fe3O4@PDA) was used as the carrier to load secondary antibody (Ab2) and horseradish peroxidase (HRP), where Fe3O4 nanoparticles and HRP can synergistically accelerate the oxidation of 4-chloro-1-naphthol (4-CN) by H2O2 to produce biocatalytic precipitation (BCP) on the surface of modified electrode. Due to the catalytic activity of Fe3O4 nanoparticles and HRP, the nonproductive absorption of HRP and the steric hindrance by BCP, the photocurrent change was amplified. The proposed PEC immunosensor can detect MC-LR in a range of 0.005–500 μg/L with a detection limit of 0.001 μg/L. Meanwhile, the PEC immunosensor exhibited high sensitivity, good stability, acceptable selectivity and reproducibility, indicating its potential application in environmental monitoring.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.035
      Issue No: Vol. 994 (2017)
       
  • A luminescent probe of mismatched DNA hybridization: Location and number
           of mismatches
    • Authors: Amira F. El-Yazbi; Alysha Wong; Glen R. Loppnow
      Pages: 92 - 99
      Abstract: Publication date: 22 November 2017
      Source:Analytica Chimica Acta, Volume 994
      Author(s): Amira F. El-Yazbi, Alysha Wong, Glen R. Loppnow
      The human genome is susceptible to change; base mismatches can arise from damaged DNA, replication errors, and spontaneous mutation, and have the potential to cause apoptosis, carcinogenesis, and mutagenesis. Many techniques have been developed for DNA mismatch detection, but many of these methods have complex, time-consuming procedures and are limited to the detection of specific types of DNA mismatches. In this work, we present a general method for the simple and sensitive nucleobase-sensitized luminescent detection of mismatches in double-stranded DNA (dsDNA) using terbium ions. Terbium ions luminesce differently depending on the site of coordination in DNA due to the proximity effect of the energy transfer process that occurs from excited, non-hydrogen bonded nucleobases in single-stranded DNA (ssDNA) regions to the terbium ions. We examined the effect of location and number of mismatches on the sensitivity and selectivity of this probe in both synthetic oligonucleotides containing mismatches and natural calf thymus DNA exposed to UV light to induce reduced base pairing due to damage. This method shows good sensitivity for the determination of DNA mismatches, with limit of detection and limit of quantification of 1 and 3 mismatches, respectively, per dsDNA sequence.
      Graphical abstract image

      PubDate: 2017-11-09T03:20:42Z
      DOI: 10.1016/j.aca.2017.09.036
      Issue No: Vol. 994 (2017)
       
  • Outside front cover
    • Abstract: Publication date: 2 January 2018
      Source:Analytica Chimica Acta, Volume 997


      PubDate: 2017-11-16T02:38:23Z
       
  • Outside front cover
    • Abstract: Publication date: 15 December 2017
      Source:Analytica Chimica Acta, Volume 996


      PubDate: 2017-11-16T02:38:23Z
       
  • Outside front cover
    • Abstract: Publication date: 1 December 2017
      Source:Analytica Chimica Acta, Volume 995


      PubDate: 2017-11-09T03:20:42Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.163.210.170
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016