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Publisher: Springer-Verlag (Total: 2570 journals)

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Showing 1 - 200 of 2570 Journals sorted alphabetically
3D Printing in Medicine     Open Access   (Followers: 4)
3D Research     Hybrid Journal   (Followers: 22, SJR: 0.222, CiteScore: 1)
4OR: A Quarterly J. of Operations Research     Hybrid Journal   (Followers: 11, SJR: 0.825, CiteScore: 1)
AAPS J.     Hybrid Journal   (Followers: 29, SJR: 1.118, CiteScore: 4)
AAPS PharmSciTech     Hybrid Journal   (Followers: 8, SJR: 0.752, CiteScore: 3)
Abdominal Radiology     Hybrid Journal   (Followers: 19, SJR: 0.866, CiteScore: 2)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 4, SJR: 0.439, CiteScore: 0)
Academic Psychiatry     Full-text available via subscription   (Followers: 30, SJR: 0.53, CiteScore: 1)
Academic Questions     Hybrid Journal   (Followers: 9, SJR: 0.106, CiteScore: 0)
Accreditation and Quality Assurance: J. for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 33, SJR: 0.316, CiteScore: 1)
Acoustical Physics     Hybrid Journal   (Followers: 11, SJR: 0.359, CiteScore: 1)
Acoustics Australia     Hybrid Journal   (Followers: 1, SJR: 0.232, CiteScore: 1)
Acta Analytica     Hybrid Journal   (Followers: 7, SJR: 0.367, CiteScore: 0)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1, SJR: 0.675, CiteScore: 1)
Acta Biotheoretica     Hybrid Journal   (Followers: 3, SJR: 0.284, CiteScore: 1)
Acta Diabetologica     Hybrid Journal   (Followers: 19, SJR: 1.587, CiteScore: 3)
Acta Endoscopica     Hybrid Journal   (Followers: 1)
acta ethologica     Hybrid Journal   (Followers: 4, SJR: 0.769, CiteScore: 1)
Acta Geochimica     Hybrid Journal   (Followers: 7, SJR: 0.24, CiteScore: 1)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 3, SJR: 0.305, CiteScore: 1)
Acta Geophysica     Hybrid Journal   (Followers: 11, SJR: 0.312, CiteScore: 1)
Acta Geotechnica     Hybrid Journal   (Followers: 7, SJR: 1.588, CiteScore: 3)
Acta Informatica     Hybrid Journal   (Followers: 5, SJR: 0.517, CiteScore: 1)
Acta Mathematica     Hybrid Journal   (Followers: 12, SJR: 7.066, CiteScore: 3)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2, SJR: 0.452, CiteScore: 1)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 6, SJR: 0.379, CiteScore: 1)
Acta Mathematica Vietnamica     Hybrid Journal   (SJR: 0.27, CiteScore: 0)
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal   (SJR: 0.208, CiteScore: 0)
Acta Mechanica     Hybrid Journal   (Followers: 24, SJR: 1.04, CiteScore: 2)
Acta Mechanica Sinica     Hybrid Journal   (Followers: 5, SJR: 0.607, CiteScore: 2)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 8, SJR: 0.576, CiteScore: 2)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.638, CiteScore: 1)
Acta Neurochirurgica     Hybrid Journal   (Followers: 7, SJR: 0.822, CiteScore: 2)
Acta Neurologica Belgica     Hybrid Journal   (Followers: 2, SJR: 0.376, CiteScore: 1)
Acta Neuropathologica     Hybrid Journal   (Followers: 4, SJR: 7.589, CiteScore: 12)
Acta Oceanologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.334, CiteScore: 1)
Acta Physiologiae Plantarum     Hybrid Journal   (Followers: 4, SJR: 0.574, CiteScore: 2)
Acta Politica     Hybrid Journal   (Followers: 19, SJR: 0.605, CiteScore: 1)
Activitas Nervosa Superior     Hybrid Journal   (SJR: 0.147, CiteScore: 0)
Adaptive Human Behavior and Physiology     Hybrid Journal  
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 9, SJR: 0.103, CiteScore: 0)
ADHD Attention Deficit and Hyperactivity Disorders     Hybrid Journal   (Followers: 28, SJR: 0.72, CiteScore: 2)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 10)
Administration and Policy in Mental Health and Mental Health Services Research     Partially Free   (Followers: 19, SJR: 1.005, CiteScore: 2)
Adolescent Research Review     Hybrid Journal   (Followers: 1)
Adsorption     Hybrid Journal   (Followers: 5, SJR: 0.703, CiteScore: 2)
Advanced Composites and Hybrid Materials     Hybrid Journal  
Advanced Fiber Materials     Full-text available via subscription  
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 4, SJR: 0.698, CiteScore: 1)
Advances in Astronautics Science and Technology     Hybrid Journal  
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 40, SJR: 0.956, CiteScore: 2)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 22, SJR: 0.812, CiteScore: 1)
Advances in Contraception     Hybrid Journal   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 58, SJR: 1.09, CiteScore: 1)
Advances in Gerontology     Partially Free   (Followers: 8, SJR: 0.144, CiteScore: 0)
Advances in Health Sciences Education     Hybrid Journal   (Followers: 35, SJR: 1.64, CiteScore: 2)
Advances in Manufacturing     Hybrid Journal   (Followers: 3, SJR: 0.475, CiteScore: 2)
Advances in Neurodevelopmental Disorders     Hybrid Journal  
Advances in Polymer Science     Hybrid Journal   (Followers: 49, SJR: 1.04, CiteScore: 3)
Advances in Therapy     Hybrid Journal   (Followers: 5, SJR: 1.075, CiteScore: 3)
Aegean Review of the Law of the Sea and Maritime Law     Hybrid Journal   (Followers: 7)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2, SJR: 0.517, CiteScore: 1)
Aerobiologia     Hybrid Journal   (Followers: 4, SJR: 0.673, CiteScore: 2)
Aerosol Science and Engineering     Hybrid Journal  
Aerospace Systems     Hybrid Journal   (Followers: 1)
Aerotecnica Missili & Spazio : J. of Aerospace Science, Technologies & Systems     Hybrid Journal  
Aesthetic Plastic Surgery     Hybrid Journal   (Followers: 11, SJR: 0.825, CiteScore: 1)
African Archaeological Review     Hybrid Journal   (Followers: 21, SJR: 0.862, CiteScore: 1)
Afrika Matematika     Hybrid Journal   (Followers: 1, SJR: 0.235, CiteScore: 0)
Ageing Intl.     Hybrid Journal   (Followers: 7, SJR: 0.39, CiteScore: 1)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
Aging Clinical and Experimental Research     Hybrid Journal   (Followers: 3, SJR: 0.67, CiteScore: 2)
Agricultural Research     Hybrid Journal   (Followers: 7, SJR: 0.276, CiteScore: 1)
Agriculture and Human Values     Open Access   (Followers: 15, SJR: 1.173, CiteScore: 3)
Agroforestry Systems     Open Access   (Followers: 20, SJR: 0.663, CiteScore: 1)
Agronomy for Sustainable Development     Open Access   (Followers: 15, SJR: 1.864, CiteScore: 6)
AI & Society     Hybrid Journal   (Followers: 9, SJR: 0.227, CiteScore: 1)
AIDS and Behavior     Hybrid Journal   (Followers: 16, SJR: 1.792, CiteScore: 3)
Air Quality, Atmosphere & Health     Hybrid Journal   (Followers: 4, SJR: 0.862, CiteScore: 3)
Akupunktur & Aurikulomedizin     Full-text available via subscription   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 7, SJR: 0.531, CiteScore: 0)
Algebra Universalis     Hybrid Journal   (Followers: 2, SJR: 0.583, CiteScore: 1)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1, SJR: 1.095, CiteScore: 1)
Algorithmica     Hybrid Journal   (Followers: 9, SJR: 0.56, CiteScore: 1)
Allergo J.     Full-text available via subscription   (Followers: 1, SJR: 0.234, CiteScore: 0)
Allergo J. Intl.     Hybrid Journal   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 5, SJR: 1.11, CiteScore: 3)
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 2)
AMBIO     Hybrid Journal   (Followers: 10, SJR: 1.569, CiteScore: 4)
American J. of Cardiovascular Drugs     Hybrid Journal   (Followers: 17, SJR: 0.951, CiteScore: 3)
American J. of Community Psychology     Hybrid Journal   (Followers: 29, SJR: 1.329, CiteScore: 2)
American J. of Criminal Justice     Hybrid Journal   (Followers: 9, SJR: 0.772, CiteScore: 1)
American J. of Cultural Sociology     Hybrid Journal   (Followers: 18, SJR: 0.46, CiteScore: 1)
American J. of Dance Therapy     Hybrid Journal   (Followers: 7, SJR: 0.181, CiteScore: 0)
American J. of Potato Research     Hybrid Journal   (Followers: 3, SJR: 0.611, CiteScore: 1)
American J. of Psychoanalysis     Hybrid Journal   (Followers: 22, SJR: 0.314, CiteScore: 0)
American Sociologist     Hybrid Journal   (Followers: 16, SJR: 0.35, CiteScore: 0)
Amino Acids     Hybrid Journal   (Followers: 7, SJR: 1.135, CiteScore: 3)
AMS Review     Partially Free   (Followers: 4)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 10, SJR: 0.211, CiteScore: 1)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 6, SJR: 0.536, CiteScore: 1)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Analysis of Verbal Behavior     Hybrid Journal   (Followers: 6)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 32, SJR: 0.978, CiteScore: 3)
Anatomical Science Intl.     Hybrid Journal   (Followers: 3, SJR: 0.367, CiteScore: 1)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3, SJR: 2.177, CiteScore: 5)
Animal Cognition     Hybrid Journal   (Followers: 23, SJR: 1.389, CiteScore: 3)
Annales françaises de médecine d'urgence     Hybrid Journal   (Followers: 1, SJR: 0.192, CiteScore: 0)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3, SJR: 1.097, CiteScore: 2)
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4, SJR: 0.438, CiteScore: 0)
Annali dell'Universita di Ferrara     Hybrid Journal   (SJR: 0.429, CiteScore: 0)
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1, SJR: 1.197, CiteScore: 1)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 19, SJR: 1.042, CiteScore: 3)
Annals of Combinatorics     Hybrid Journal   (Followers: 4, SJR: 0.932, CiteScore: 1)
Annals of Data Science     Hybrid Journal   (Followers: 13)
Annals of Dyslexia     Hybrid Journal   (Followers: 10, SJR: 0.85, CiteScore: 2)
Annals of Finance     Hybrid Journal   (Followers: 35, SJR: 0.579, CiteScore: 1)
Annals of Forest Science     Hybrid Journal   (Followers: 7, SJR: 0.986, CiteScore: 2)
Annals of Global Analysis and Geometry     Hybrid Journal   (Followers: 1, SJR: 1.228, CiteScore: 1)
Annals of Hematology     Hybrid Journal   (Followers: 15, SJR: 1.043, CiteScore: 2)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 13, SJR: 0.413, CiteScore: 1)
Annals of Microbiology     Hybrid Journal   (Followers: 13, SJR: 0.479, CiteScore: 2)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 5, SJR: 0.687, CiteScore: 2)
Annals of Operations Research     Hybrid Journal   (Followers: 11, SJR: 0.943, CiteScore: 2)
Annals of Ophthalmology     Hybrid Journal   (Followers: 13)
Annals of PDE     Hybrid Journal  
Annals of Regional Science     Hybrid Journal   (Followers: 9, SJR: 0.614, CiteScore: 1)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annals of Solid and Structural Mechanics     Hybrid Journal   (Followers: 11, SJR: 0.239, CiteScore: 1)
Annals of Surgical Oncology     Hybrid Journal   (Followers: 15, SJR: 1.986, CiteScore: 4)
Annals of Telecommunications     Hybrid Journal   (Followers: 9, SJR: 0.223, CiteScore: 1)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1, SJR: 1.495, CiteScore: 1)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5, SJR: 0.834, CiteScore: 2)
Apidologie     Hybrid Journal   (Followers: 4, SJR: 1.22, CiteScore: 3)
APOPTOSIS     Hybrid Journal   (Followers: 9, SJR: 1.424, CiteScore: 4)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 3, SJR: 0.294, CiteScore: 1)
Applications of Mathematics     Hybrid Journal   (Followers: 3, SJR: 0.602, CiteScore: 1)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 44, SJR: 0.571, CiteScore: 2)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 19, SJR: 0.21, CiteScore: 1)
Applied Categorical Structures     Hybrid Journal   (Followers: 4, SJR: 0.49, CiteScore: 0)
Applied Composite Materials     Hybrid Journal   (Followers: 53, SJR: 0.58, CiteScore: 2)
Applied Entomology and Zoology     Partially Free   (Followers: 7, SJR: 0.422, CiteScore: 1)
Applied Geomatics     Hybrid Journal   (Followers: 3, SJR: 0.733, CiteScore: 3)
Applied Geophysics     Hybrid Journal   (Followers: 9, SJR: 0.488, CiteScore: 1)
Applied Intelligence     Hybrid Journal   (Followers: 15, SJR: 0.6, CiteScore: 2)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4, SJR: 0.319, CiteScore: 1)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 10, SJR: 0.886, CiteScore: 1)
Applied Mathematics - A J. of Chinese Universities     Hybrid Journal   (Followers: 1, SJR: 0.17, CiteScore: 0)
Applied Mathematics and Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.461, CiteScore: 1)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 68, SJR: 1.182, CiteScore: 4)
Applied Physics A     Hybrid Journal   (Followers: 10, SJR: 0.481, CiteScore: 2)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 26, SJR: 0.74, CiteScore: 2)
Applied Psychophysiology and Biofeedback     Hybrid Journal   (Followers: 8, SJR: 0.519, CiteScore: 2)
Applied Research in Quality of Life     Hybrid Journal   (Followers: 12, SJR: 0.316, CiteScore: 1)
Applied Solar Energy     Hybrid Journal   (Followers: 22, SJR: 0.225, CiteScore: 0)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 6, SJR: 0.542, CiteScore: 1)
Aquaculture Intl.     Hybrid Journal   (Followers: 26, SJR: 0.591, CiteScore: 2)
Aquarium Sciences and Conservation     Hybrid Journal   (Followers: 2)
Aquatic Ecology     Hybrid Journal   (Followers: 37, SJR: 0.656, CiteScore: 2)
Aquatic Geochemistry     Hybrid Journal   (Followers: 3, SJR: 0.591, CiteScore: 1)
Aquatic Sciences     Hybrid Journal   (Followers: 14, SJR: 1.109, CiteScore: 3)
Arabian J. for Science and Engineering     Hybrid Journal   (Followers: 5, SJR: 0.303, CiteScore: 1)
Arabian J. of Geosciences     Hybrid Journal   (Followers: 2, SJR: 0.319, CiteScore: 1)
Archaeological and Anthropological Sciences     Hybrid Journal   (Followers: 22, SJR: 1.052, CiteScore: 2)
Archaeologies     Hybrid Journal   (Followers: 13, SJR: 0.224, CiteScore: 0)
Archiv der Mathematik     Hybrid Journal   (Followers: 1, SJR: 0.725, CiteScore: 1)
Archival Science     Hybrid Journal   (Followers: 68, SJR: 0.745, CiteScore: 2)
Archive for History of Exact Sciences     Hybrid Journal   (Followers: 7, SJR: 0.186, CiteScore: 1)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 3, SJR: 0.909, CiteScore: 1)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (SJR: 3.93, CiteScore: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 6, SJR: 0.79, CiteScore: 2)
Archives and Museum Informatics     Hybrid Journal   (Followers: 176, SJR: 0.101, CiteScore: 0)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 6, SJR: 1.41, CiteScore: 5)
Archives of Dermatological Research     Hybrid Journal   (Followers: 7, SJR: 1.006, CiteScore: 2)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 14, SJR: 0.773, CiteScore: 2)
Archives of Gynecology and Obstetrics     Hybrid Journal   (Followers: 18, SJR: 0.956, CiteScore: 2)
Archives of Microbiology     Hybrid Journal   (Followers: 10, SJR: 0.644, CiteScore: 2)
Archives of Orthopaedic and Trauma Surgery     Hybrid Journal   (Followers: 9, SJR: 1.146, CiteScore: 2)
Archives of Osteoporosis     Hybrid Journal   (Followers: 2, SJR: 0.71, CiteScore: 2)
Archives of Sexual Behavior     Hybrid Journal   (Followers: 11, SJR: 1.493, CiteScore: 3)
Archives of Toxicology     Hybrid Journal   (Followers: 18, SJR: 1.541, CiteScore: 5)
Archives of Virology     Hybrid Journal   (Followers: 5, SJR: 0.973, CiteScore: 2)
Archives of Women's Mental Health     Hybrid Journal   (Followers: 17, SJR: 1.274, CiteScore: 3)
Archivio di Ortopedia e Reumatologia     Hybrid Journal  
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2, SJR: 0.946, CiteScore: 3)
ArgoSpine News & J.     Hybrid Journal  
Argumentation     Hybrid Journal   (Followers: 6, SJR: 0.349, CiteScore: 1)
Arid Ecosystems     Hybrid Journal   (Followers: 3, SJR: 0.2, CiteScore: 0)
Arkiv för Matematik     Hybrid Journal   (Followers: 1, SJR: 0.766, CiteScore: 1)
arktos : The J. of Arctic Geosciences     Hybrid Journal  
Arnold Mathematical J.     Hybrid Journal   (Followers: 1, SJR: 0.355, CiteScore: 0)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 2, SJR: 0.839, CiteScore: 2)
Arthroskopie     Hybrid Journal   (Followers: 1, SJR: 0.131, CiteScore: 0)
Artificial Intelligence and Law     Hybrid Journal   (Followers: 12, SJR: 0.937, CiteScore: 2)
Artificial Intelligence Review     Hybrid Journal   (Followers: 22, SJR: 0.833, CiteScore: 4)
Artificial Life and Robotics     Hybrid Journal   (Followers: 10, SJR: 0.226, CiteScore: 0)
Asia Europe J.     Hybrid Journal   (Followers: 4, SJR: 0.504, CiteScore: 1)
Asia Pacific Education Review     Hybrid Journal   (Followers: 12, SJR: 0.479, CiteScore: 1)
Asia Pacific J. of Management     Hybrid Journal   (Followers: 17, SJR: 1.185, CiteScore: 2)

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Similar Journals
Journal Cover
Analytical and Bioanalytical Chemistry
Journal Prestige (SJR): 0.978
Citation Impact (citeScore): 3
Number of Followers: 32  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1618-2650 - ISSN (Online) 1618-2642
Published by Springer-Verlag Homepage  [2570 journals]
  • Basem Kanawati and Philippe Schmitt-Kopplin (Eds.): Fundamentals and
           applications of Fourier transform mass spectrometry
    • PubDate: 2019-12-04
       
  • Simultaneous determination of 44 pharmaceutically active compounds in
           water samples using solid-phase extraction coupled with ultra-performance
           liquid chromatography-tandem mass spectrometry
    • Abstract: Abstract This study examines an improved and simplified method for solid-phase extraction (SPE), which offers rapid and accurate determination and identification of 44 pharmaceutically active compounds using ultra-performance liquid chromatography (UPLC) and tandem mass spectrometry (MS/MS). The common active compounds include four macrolides, seventeen sulfonamides, four quinolones, chloramphenicol, eight β-lactams, four tetracyclines, lincomycin, amantadine, 4-acetamidophenol, phenylbutazone, trimethoprim, clenbuterol, and hydrocortisone in water samples. We optimized crucial parameters of MS/MS, UPLC, and SPE and studied the matrix effect related to the modified analytical process from water samples. The matrix-matched calibration curves were accomplished at seven concentration levels and a satisfactory linear relationship (r2 > 0.994) was observed within the range of 0.1–500 ng/mL. Results show varying limits of detection (0.0111–0.966 ng/L for different analytes based on signal-to-noise (S/N) = 3) and limits of quantitation (0.0382–3.26 ng/L). Recoveries of the spiked samples ranged from 75.7 to 108% with relative standard deviation lower than 9.6%. The proposed method was successfully applied to the analysis of real samples.
      PubDate: 2019-12-04
       
  • Probeless non-invasive near-infrared spectroscopic bioprocess monitoring
           using microspectrometer technology
    • Abstract: Real-time measurements and adjustments of critical process parameters are essential for the precise control of fermentation processes and thus for increasing both quality and yield of the desired product. However, the measurement of some crucial process parameters such as biomass, product, and product precursor concentrations usually requires time-consuming offline laboratory analysis. In this work, we demonstrate the in-line monitoring of biomass, penicillin (PEN), and phenoxyacetic acid (POX) in a Penicilliumchrysogenum fed-batch fermentation process using low-cost microspectrometer technology operating in the near-infrared (NIR). In particular, NIR reflection spectra were taken directly through the glass wall of the bioreactor, which eliminates the need for an expensive NIR immersion probe. Furthermore, the risk of contaminations in the reactor is significantly reduced, as no direct contact with the investigated medium is required. NIR spectra were acquired using two sensor modules covering the spectral ranges 1350–1650 nm and 1550–1950 nm. Based on offline reference analytics, partial least squares (PLS) regression models were established for biomass, PEN, and POX either using data from both sensors separately or jointly. The established PLS models were tested on an independent validation fed-batch experiment. Root mean squared errors of prediction (RMSEP) were 1.61 g/L, 1.66 g/L, and 0.67 g/L for biomass, PEN, and POX, respectively, which can be considered an acceptable accuracy comparable with previously published results using standard process spectrometers with immersion probes. Altogether, the presented results underpin the potential of low-cost microspectrometer technology in real-time bioprocess monitoring applications. Graphical abstract
      PubDate: 2019-12-04
       
  • Online monitoring of the cell-specific oxygen uptake rate with an in situ
           combi-sensor
    • Abstract: Abstract In a biotechnological process, standard monitored process variables are pH, partial oxygen pressure (pO2), and temperature. These process variables are important, but they do not give any information about the metabolic activity of the cell. The ISICOM is an in situ combi-sensor that is measuring the cell-specific oxygen uptake rate (qOUR) online. This variable allows a qualitative judgement of metabolic cell activity. The measuring principle of the ISICOM is based on a volume element enclosed into a small measuring chamber. Inside the measuring chamber, the pO2 and the scattered light is measured. Within a defined measuring interval, the chamber closes, and the oxygen supply for the cells is interrupted. The decreasing oxygen concentration is recorded by the pO2 optode. This measuring principle, known as the dynamic method, determines the oxygen uptake rate (OUR). Together with the scattered light signal, the cell concentration is estimated and the qOUR is available online. The design of the ISICOM is focused on functionality, sterility, long-term stability, and response time behavior so the sensor can be used in bioprocesses. With the ISICOM, measurement of online and in situ measurement of the OUR is possible. The OUR and qOUR online measurement of an animal cell batch cultivation is demonstrated, with maximum values of OUR = 2.5 mmol L−1 h−1 and a qOUR = 9.5 pmol cell−1 day−1. Information about limitation of the primary and secondary substrate is derived by the monitoring of the metabolic cell activity of bacteria and yeast cultivation processes. This sensor contributes to a higher process understanding by offering an online view on to the cell behavior. In the sense of process analytical technology (PAT), this important information is needed for bioprocesses to realize a knowledge base process control.
      PubDate: 2019-12-04
       
  • Highly sensitive real-time PCR method to identify species origin in
           heparinoids
    • Abstract: Abstract Heparinoids are the starting material for sulodexide production, a drug used as intravenous anti-coagulant, as an alternative to heparin. The origin determination in the starting material for sulodexide, heparin, and derivatives is crucial for safety (including the impact related to bovine spongiform encephalopathy) and efficacy of the final products. Therefore, European countries have decided to approve the production of heparin only from porcine intestinal mucosa. PCR (polymerase chain reaction) methods are available to evaluate the origin species of crude heparin, during heparin production process, while they lack for the same analysis in heparinoids during sulodexide manufacturing processes. Notably, two main critical issues occur during the origin determination by using PCR for heparinoid analysis: first, heparin has been known to inhibit DNA polymerase activity and, second, the DNA amounts are very low in these samples. To overcome these critical issues, our proposed method is based on two fundamental steps, the DNA concentration by glycogen treatment and DNA purification, which occur before and after DNA extraction, respectively. Finally, by applying real-time PCR, we amplify three specific DNA sequences of ruminant species (bovine, ovine, and caprine), to assess possible contamination, and one from swine, to confirm the origin species. To date, such a method is the only one that determines origin species by PCR for heparinoids that guarantee quality, safety, and traceability of heparin-derived pharmaceutical products. In conclusion, our proposed method is an alternative to nuclear magnetic resonance and ELISA methods, because real-time PCR offers significant advantages in sensitivity, specificity, and robustness. Graphical Abstract
      PubDate: 2019-12-04
       
  • Optimization of protein isolation by proteomic qualification from
           Cutaneotrichosporon oleaginosus
    • Abstract: In the last decades, microbial oils have been extensively investigated as a renewable platform for biofuel and oleochemical production. Offering a potent alternative to plant-based oils, oleaginous microorganisms have been the target of ongoing metabolic engineering aimed at increasing growth and lipid yields, in addition to specialty fatty acids. Discovery proteomics is an attractive tool for elucidating lipogenesis and identifying metabolic bottlenecks, feedback regulation, and competing biosynthetic pathways. One prominent microbial oil producer is Cutaneotrichosporon oleaginosus, due to its broad feedstock catabolism and high lipid yield. However, this yeast has a recalcitrant cell wall and high cell lipid content, which complicates efficient and unbiased protein extraction for downstream proteomic analysis. Optimization efforts of protein sample preparation from C. oleaginosus in the present study encompasses the comparison of 8 lysis methods, 13 extraction buffers, and 17 purification methods with respect to protein abundance, proteome coverage, applicability, and physiochemical properties (pI, MW, hydrophobicity in addition to COG, and GO analysis). The optimized protocol presented in this work entails a one-step extraction method utilizing an optimal lysis method (liquid homogenization), which is augmented with a superior extraction buffer (50 mM Tris, 8/2 M Urea/Thiourea, and 1% C7BzO), followed by either of 2 advantageous purification methods (hexane/ethanol or TCA/acetone), depending on subsequent applications and target studies. This work presents a significant step forward towards implementation of efficient C. oleaginosus proteome mining for the identification of potential targets for genetic optimization of this yeast to improve lipogenesis and production of specialty lipids. Graphical abstract
      PubDate: 2019-12-04
       
  • Differences in the lipid patterns during maturation of 3T3-L1 adipocytes
           investigated by thin-layer chromatography, gas chromatography, and mass
           spectrometric approaches
    • Abstract: Populations of industrialized countries have registered a dramatically increasing prevalence in obesity for many years. Despite continuous research, mechanisms involved in the storage and utilization of chemical energy in adipocytes are still under investigation. Adipocytes have the task to store excessive energy in the form of triacylglycerols (TG) and it is already well-known that the fatty acyl composition of TG is largely determined by the composition of the diet. In contrast to TG, the composition of adipocyte phospholipids was less comprehensively investigated. In this study, the compositions of the most abundant phospholipid classes of 3T3-L1 undifferentiated (preadipocytes) and differentiated cells (adipocytes) were determined. The lipid fractions were isolated by normal phase high-performance thin-layer chromatography and subsequently analyzed by electrospray ionization mass spectrometry. Additionally, the fatty acyl (FA) compositions were determined by gas chromatography. The positions of the FA residues were additionally confirmed by phospholipase A2 digestion. The advantages and disadvantages of the different analytical approaches will be discussed. It will be shown that undifferentiated 3T3-L1 and mature adipocytes differ extremely regarding their compositions. This goes along with an increase in odd-chain fatty acids. Graphical abstract
      PubDate: 2019-12-03
       
  • Detection of recombinant insulins in human urine by liquid
           chromatography–electrospray ionization tandem mass spectrometry after
           immunoaffinity purification based on monolithic microcolumns
    • Abstract: This work describes an analytical procedure based on automated affinity purification followed by liquid chromatography–electrospray tandem mass spectrometry with a conventional triple quadrupole analyzer, in order to detect synthetic insulins (Apidra®, Humalog®, Levemir®, NovoRapid®, and Tresiba®) in human urine. Sample preparation included ultrafiltration followed by immunoaffinity purification on monolithic microcolumns. Chromatographic separation was performed by a C18 microbore column, while mass spectrometric identification of the analytes was achieved by a triple quadrupole mass spectrometer under positive ion electrospray ionization and acquisition mode in selected reaction monitoring. Identification of the synthetic insulins was performed by selecting at least two characteristic ion transitions for each analyte. The newly developed method was validated in terms of specificity, recovery, matrix effect, sensitivity, robustness, and repeatability of retention times and relative ion transition abundance. The specificity and the reproducibility of the relative retention times and the relative abundance of the characteristic ion transitions selected was confirmed to be fit for purposes of ensuring the unambiguous identification of all target analytes, also in the forensic field. The extraction yield was estimated at greater than 60% and the matrix effect smaller than 35%. The lower limits of detection were in the range of 0.02–0.05 ng/mL, proving the method to be sufficiently sensitive to detect the abuse of insulins in cases where they are used as performance-enhancing agents in sport. The applicability of the developed method was assessed by the analysis of urine samples obtained from diabetic subjects treated with Tresiba® and/or Humalog®, whose presence was confirmed in urine samples collected after the administration of therapeutic doses. Graphical abstract A hybrid assay comprising MSIA-based immunoextraction combined with liquid chromatography–electrospray tandem mass spectrometry was developed and validated for the detection of recombinant insulins in human urine.
      PubDate: 2019-12-03
       
  • Single sample preparation for brominated flame retardants in fish and
           shellfish with dual detection: GC-MS/MS (PBDEs) and LC-MS/MS (HBCDs)
    • Abstract: Abstract An analytical method for the simultaneous determination of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in fish, shellfish and muscle of terrestrial animals was developed as an extension of a previously validated method for PBDE analysis. A single sample preparation based on QuEChERS-like extraction and a two-step clean-up, followed by a dual instrumental detection, was implemented. GC-MS/MS was used for PBDEs and LC-MS/MS for HBCDs. The method allows the quantification of fifteen PBDEs (28, 47, 49, 66, 77, 85, 99, 100, 138, 153, 154, 183, 197, 206, 209) and three HBCD isomers (α, β and γ), reaching 10 pg/g LOQs for all the analytes except BDE 206 and 209 (100 pg/g LOQ). The validated method was applied to the analysis of 12 fish and shellfish species (sole, spiny dogfish, smooth-hound, mackerel, swordfish, grey mullet, cod, anchovy, red mullet, Atlantic horse mackerel, tuna fish and mussel) collected in central Italian markets accounting for a total of 44 samples. Generally, ΣPBDEs showed higher concentration than ΣHBCDs except in the case of mussels in which ΣHBCDs > ΣPBDEs. Cod and smooth-hound are the least contaminated species among those analysed in the present study, whereas the highest brominated flame retardant (BFR) levels were found in spiny dogfish samples. The measured contamination levels were generally comparable to or lower than those already published in European studies. Literature data for HBCDs in European fish and shellfish were hard to find; therefore, PBDE and HBCD levels were also compared with European Environmental Quality Standard (EQS) in biota (Directive 2013/39/EU). EQSs for HBCDs are six orders of magnitude higher than those for PBDEs; therefore, while no exceedance was observed for the first, almost all the samples analysed for PBDEs were above EQSs. The presented preliminary data on PBDEs and HBCDs are among the first published in marine fish and shellfish commercialised in Central Italy. Graphical abstrac
      PubDate: 2019-12-03
       
  • Rapid visualized isothermal nucleic acid testing of Vibrio
           parahaemolyticus by polymerase spiral reaction
    • Abstract: Abstract The aim of this study was to develop an effective and specific visual method to rapidly detect and identify Vibrio parahaemolyticus (V. parahaemolyticus) based on the polymerase spiral reaction (PSR). The method utilized only two pairs of primers designed specifically to target the conserved tlh gene sequence of V. parahaemolyticus. Nucleic acid amplification can be achieved under isothermal conditions using DNA polymerase. The reaction could be accomplished in < 40 min with high specificity and sensitivity. The limits of detection of V. parahaemolyticus in purified genomic DNA and pure culture were 300 fg/μL and 2.4 CFU/mL per reaction, respectively, which were 100-fold more sensitive than with conventional PCR. The model food samples showed consistent specificity and sensitivity to the pure bacterial culture. With these encouraging results, it is expected that the novel, effortless and reliable isothermal nucleic acid testing assay developed in this study has potential to be applied to screening for V. parahaemolyticus in seafood samples.
      PubDate: 2019-12-03
       
  • A microfluidic device enabling surface-enhanced Raman spectroscopy at
           chip-integrated multifunctional nanoporous membranes
    • Abstract: Abstract A three-dimensional microfluidic chip that combines sample manipulation and SERS detection on-chip was developed. This was successfully achieved by chip integration of a nanoporous polycarbonate track-etched (PCTE) membrane which connects microfluidic channels on two different levels with each other. The membrane fulfills two functions at the same time. On the one hand, it enables sample enrichment by selective electrokinetic transport processes through the membrane. On the other hand, the silver nanoparticle–coated backside of the same membrane enables SERS detection of the enriched analytes. The SERS substrate performance and the electrokinetic transport phenomena were studied using Rhodamine B (RhB) by Raman microscopy and fluorescence video microscopy. After system validation, the approach was attested by on-chip processing of a complex food sample. In a proof-of-concept study, the microfluidic device with the SERS substrate membrane was used to detect a concentration of 1 ppm melamine (705 cm−1) in whole milk. Electrokinetic transport across the nanoporous SERS substrate facilitates the extraction of analyte molecules from a sample channel into a detection channel via a potential gradient, thus easily removing obscuring compounds present in the sample matrix. The SERS signal of the analyte could be significantly increased by on-target sample drying. This was achieved by guiding an additional gas flow over the membrane which further extends the microfluidic functionality of the chip device. The proposed method possesses the advantages of combining a rapid (within 15 min) sample clean-up using electrokinetic transport in a three-dimensional microfluidic device which is highly suitable for sensitive and selective SERS detection of chemical and biological analytes. Graphical Abstract
      PubDate: 2019-12-03
       
  • A novel analytical method for simple and low-cost detection of isocyanates
           in ambient air
    • Abstract: Abstract In this study, we developed a novel method for the collection of gaseous and particulate isocyanates in the air using di-n-butylamine (DBA)-coated glass fiber filters and a cation-exchange column (GFF_SCX-DBA) sampler. Our method showed acceptable linearity, accuracy, and precision in the analysis of eleven kinds of isocyanates (ICA, MIC, EIC, PIC, PHI, 1,6-HDI, 2,4-TDI, 2,6-TDI, trans-IPDI, cis-IPDI, and 4,4′-MDI). And, some of them were detected in the air at the plant manufacturing isocyanates and spray polyurethane foam. Actually, 2,4-TDI and 2,6-TDI (11,000 ± 6600 and 5800 ± 3500 ng/m3, respectively) were detected at much higher levels than others at the plant manufacturing isocyanates, and the levels of these isocyanates were comparable with those obtained by using the commercial sampler. Furthermore, PHI and 4,4′-MDI (5800 ± 470 and 3500 ± 1100 ng/m3, respectively) were detected at a relatively higher concentration than the others in the place of spray polyurethane foam. Through this study, we realized that the concentration of isocyanates in various working places could be analyzed using our GFF_SCX-DBA sampler. This method makes it possible to perform a rapid and simplified extraction operation in a shorter time than in the commercial sampler by combining the GFF and SCX samplers.
      PubDate: 2019-12-02
       
  • Trace-level determination of phosphonates in liquid and solid phase of
           wastewater and environmental samples by IC-ESI-MS/MS
    • Abstract: Phosphonates are increasingly used as water-softening agents in detergents, care products, and industrial processes. Despite poor biodegradability, high removal rates during wastewater treatment (WWT) have been observed, owing to strong adsorption affinity to activated sludge and mineral surfaces. Due to phosphonates representing challenging analytes, no method for the compound-specific quantification of phosphonates from solid samples has hitherto been published. In order to improve the data foundation on the environmental fate of phosphonates, an analytical method based on anion exchange chromatography and detection by electrospray ionization coupled to tandem mass spectrometry (IC-ESI-MS/MS) was developed, allowing the trace quantification of phosphonates from surface water (LOQs between 0.04 and 0.16 μg/L), wastewater (LOQs between 0.6 and 2.3 μg/L), sediment and suspended matter of rivers (LOQ < 0.1 mg/kg), and suspended matter of wastewater (LOQ < 1 mg/kg). Specificity and selectivity were enhanced by the implementation of isotope-labeled internal phosphonate standards derived through synthesis. This study describes the development of a comprehensive tool set for the determination of aminotris(methylenephosphonic acid) (ATMP), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), ethylenediaminetetra(methylenephosphonic acid) (EDTMP), 1-hydroxyethanediphosphonic acid (HEDP), and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) during WWT and in the aqueous environment. In the investigated matrices, HEDP and PBTC were generally present in highest and EDTMP in lowest abundance. The phosphonate contents detected in river water were in the sub to low μg/L range, depending on the wastewater burden, whereas contents in the low to medium μg/L range were found in untreated wastewater. The loads of the solid phases exceeded the contents of the corresponding liquid phases by roughly three orders of magnitude. Current data imply that phosphonates undergo significant partitioning to the solid phase during WWT and in natural water bodies. Graphical abstract
      PubDate: 2019-12-02
       
  • A rapid method for on-line solid-phase extraction and determination of
           dioscin in human plasma using a homemade monolithic sorbent combined with
           high-performance liquid chromatography
    • Abstract: A phenyl-based polymer monolithic column was prepared via free radical polymerization in a stainless steel column with the size of 4.6 mm i.d. × 50 mm, using ethylene glycol phenyl ether acrylate as the monomer. The resulting monolithic column shows high porosity of 73.42% and relative uniform pore structure, as characterized by mercury porosimetry and scanning electron microscopy, respectively. The optimized polymer monolith column was used for on-line solid-phase extraction prior to the reversed phase mode HPLC-UV analysis for the determination of dioscin in human plasma, using a COSMOSIL C18 column (4.6 mm × 150 mm, 4.5 μm). Water was used to wash non-retained components from the SPE sorbent, and methanol water (80:20, V/V) was used as the mobile phase for isocratic elution of dioscin. The maximum adsorbed quantity of dioscin to the SPE column is 6.79 mg/g, which is high enough for the quantitative analysis of dioscin in plasma, due to the low content of dioscin in plasma. The method was validated by assessing the linearity, lower limit of quantification, intra- and inter-day precision, accuracy, and repeatability. The developed method was applied for the analysis of dioscin in plasma from a volunteer who had orally administered an aqueous extract of dioscorea nipponica rhizome, showing the method capable of detecting dioscin in the plasma. These results show that the developed method is a rapid method for on-line solid-phase extraction and determination of dioscin from plasma, exhibiting good selectivity with hydrogen bond interaction and hydrophobic interaction, good clean-up ability, cost-saving, and time-saving. Graphical abstract
      PubDate: 2019-12-02
       
  • In vitro metabolism of triclosan studied by liquid
           chromatography–high-resolution tandem mass spectrometry
    • Abstract: Triclosan (TCS) is an antibacterial and antifungal compound found in many hygiene products, including toothpaste, soap, and detergents. However, this molecule can act as an endocrine disruptor and can induce harmful effects on human health and the environment. In this study, triclosan was biotransformed in vitro using human and rat liver fractions, to evaluate oxidative metabolism, the formation of reactive metabolites via the detection of GSH adducts, as well as glucuronide and sulfate conjugates using liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-HRMS/MS). A deuterated analog of triclosan was also employed for better structural elucidation of specific metabolic sites. Several GSH adducts were found, either via oxidative metabolism of triclosan or its cleavage product, 2,4-dichlorophenol. We also detected glucuronide and sulfated conjugates of triclosan and its cleaved product. This study was aimed at understanding the routes of detoxification of this xenobiotic, as well as investigating any potential pathways related to additional toxicity via reactive metabolite formation. Graphical abstract
      PubDate: 2019-12-01
       
  • Flavonoid aglycone–oriented data-mining in high-performance liquid
           chromatography–quadrupole time-of-flight tandem mass spectrometry:
           efficient and targeted profiling of flavonoids in Scutellaria barbata
    • Abstract: The high-performance liquid chromatography–quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) technique is a powerful tool for compound identification in complex natural products. However, untargeted MS/MS data analysis needs skillful experience and sometimes neglects minor compounds, which are co-eluted with major ones or overshadowed by the matrix. Flavonoids are the main bioactive components in Scutellaria barbata, and the total flavonoid content is 47.02 ± 3.23 mg QE/g DW. Although some flavonoid aglycones and their O-glycosides have been found in S. barbata, comprehensive profiling of flavonoids is unknown. Therefore, we report a flavonoid aglycone–oriented data-mining strategy for efficient and targeted profiling of flavonoids in S. barbata. The strategy includes four steps: (1) HPLC-QTOF-MS analysis of S. barbata; (2) construction of a flavonoid aglycone–based database according to biosynthetic pathway analysis and reported data; (3) extraction of through flavonoid aglycone–based ion chromatography; (4) identification of targeted flavonoids by MS/MS analysis. As a result, 45 flavonoids, including 24 flavones, 1 flavonol, 13 flavanones, and 7 flavanonols, were unambiguously or tentatively identified, while 20 of them were reported in S. barbata for the first time. Moreover, 14 available flavonoids were sensitively, precisely, and accurately determined by standard calibration curves, with limit of detection at 0.06 to 1.55 μg/g, limit of quantification at 0.16 to 3.70 μg/g, relative standard deviation (RSD) less than 9.0% for intra- and inter-day variations, and recovery at 92.6–108.1%. The matrix did not obviously suppress or enhance the ionization of 14 flavonoids, and finally their contents ranging from 0.04 to 4.49 mg/g in S. barbata were successfully achieved. Collectively, our results demonstrate that an efficient, reliable, and valuable strategy has been provided to rapidly and sensitively screen, profile, and quantify chemical components of complex natural products. Graphical abstract
      PubDate: 2019-11-30
       
  • pH dependence of water anomaly temperature investigated by Eu(III)
           cryptate luminescence
    • Abstract: Although water has been extensively studied, not all of its unique properties have been fully understood. There is still controversy about the temperature at which hydrogen bonds are broken or weakened, producing the anomalous temperature dependence of many water properties. Different temperatures between 23 and 48 °C have been reported, but no study has scrutinized the reasons for this discrepancy. We suggest the determining role of pH in the alteration of the water anomaly temperature. We employed a luminescent europium trisbipyridine cryptate, which is highly sensitive to changes in the arrangement of water molecules and whose luminescence intensity and lifetime are not significantly influenced by variations over a broad pH range. Our results revealed an increase of the crossover temperature from circa 35 °C at pH 3.5 to circa 45 °C at pH 7 to 9, which explains the discrepancies of previous studies. The pH dependence of water anomaly temperature is an important property for a better understanding of water and water-based systems and applications.
      PubDate: 2019-11-28
       
  • Ultrasensitive dual-color rapid lateral flow immunoassay via gold
           nanoparticles with two different morphologies for the serodiagnosis of
           human brucellosis
    • Abstract: Lateral flow immunoassays (LFIAs) are popular because they are rapid, convenient, stable, low cost, and easy to read. However, conventional LFIAs based on gold nanoparticles lack sensitivity, which hinders their widespread use. Here, we prepared durian-like gold nanoparticles (GNDs) and labeled them with staphylococcal protein A to detect brucella antibody. Then, the analytical performances of GNDs and gold nanospheres (GNSs) with the same diameter were compared. It was found that the sensitivity of GNDs was five to ten times higher than that of GNSs. The nonspherical morphologies of the nanoparticles greatly increased the sensitivity of the LFIA. On the basis of GNDs and GNSs, we developed an ultrasensitive dual-color brucellosis LFIA. GNSs labeled with streptavidin were used to demonstrate the control line. This dual-color LFIA had a diagnostic sensitivity and specificity of 100%. Human standard Brucella-positive serum (containing brucella antibody at 4000 IU/mL) could be detected in this system even for a dilution factor of 10−5. The detection limit was 0.04 IU/mL. This is two orders of magnitude better than conventional LFIA strips (detection limit 4 IU/mL). This dual-color LFIA contains all components of a conventional LFIA with no additional processing steps or reagents. It can detect antibodies in serum, plasma, and even whole blood without sample pretreatment or blood filtration pads. Both types of nanoparticles were synthesized in a simple and low-cost manner. This suggests that it will have utility for the early diagnosis of brucellosis and other diseases. Graphical abstract
      PubDate: 2019-11-28
       
  • Separation of nanoparticles from polydisperse environmental samples:
           comparative study of filtration, sedimentation, and coiled tube field-flow
           fractionation
    • Abstract: Abstract Nanoparticles (NPs) in the environment have a potential risk for human health and the ecosystem due to their ubiquity, specific characteristics, and properties (extreme mobility in the environment, abilities to accumulate of toxic elements and penetrate into living organisms). There is still a gap in studies on the chemical composition of natural NPs. The main reason is the difficulty to recover NPs, which may represent only one-thousandth or less of the bulk environmental sample, for further dimensional and quantitative characterization. In the present study, a methodology for the recovery of the nanoparticle fraction from polydisperse environmental samples was developed taking as example volcanic ashes from different regions of the world. For the first time, three separation methods, namely, filtration through a 0.45-μm membrane, sedimentation, and coiled tube field-flow fractionation (CTFFF), were comparatively studied. The separated fractions were characterized by laser diffraction and scanning electron microscopy and then analyzed by inductively coupled plasma atomic emission and mass spectrometry. It has been shown that all three methods provide the separation of NPs less than 400 nm from the bulk material. However, the fraction separated by sedimentation also contained a population (5% in mass) of submicron particles (~ 400–900 nm). The filtration resulted in low recovery of NPs. The determination of most trace elements was then impossible; the concentration of elements was under the limit of detection of the analytical instrument. The sedimentation and CTFFF made it possible to determine quantifiable concentrations for both major and trace elements in separated fractions. However, the sedimentation took 48 h while CTFFF enabled the fractionation time to be decreased down to 2 h. Hence, CTFFF looked to be the most promising method for the separation of NPs followed by their quantitative elemental analysis.
      PubDate: 2019-11-28
       
  • Stig Pedersen-Bjergaard, Bente Gammelgaard, and Trine Grønhaug Halvorsen:
           Introduction to pharmaceutical analytical chemistry, 2nd ed.
    • PubDate: 2019-11-27
       
 
 
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