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Publisher: Springer-Verlag (Total: 2354 journals)

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Showing 1 - 200 of 2354 Journals sorted alphabetically
3D Research     Hybrid Journal   (Followers: 18, SJR: 0.214, h-index: 10)
4OR: A Quarterly J. of Operations Research     Hybrid Journal   (Followers: 10, SJR: 1.073, h-index: 25)
AAPS J.     Hybrid Journal   (Followers: 20, SJR: 1.192, h-index: 74)
AAPS PharmSciTech     Hybrid Journal   (Followers: 6, SJR: 0.718, h-index: 54)
Abdominal Imaging     Hybrid Journal   (Followers: 14, SJR: 0.723, h-index: 60)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 3, SJR: 0.447, h-index: 12)
Academic Psychiatry     Full-text available via subscription   (Followers: 23, SJR: 0.492, h-index: 32)
Academic Questions     Hybrid Journal   (Followers: 8, SJR: 0.135, h-index: 6)
Accreditation and Quality Assurance: J. for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26, SJR: 0.378, h-index: 30)
Acoustical Physics     Hybrid Journal   (Followers: 11, SJR: 0.355, h-index: 20)
Acoustics Australia     Hybrid Journal  
Acta Analytica     Hybrid Journal   (Followers: 7, SJR: 0.387, h-index: 6)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1, SJR: 0.624, h-index: 34)
Acta Biotheoretica     Hybrid Journal   (Followers: 5, SJR: 0.419, h-index: 25)
Acta Diabetologica     Hybrid Journal   (Followers: 14, SJR: 1.318, h-index: 46)
Acta Endoscopica     Hybrid Journal   (Followers: 1, SJR: 0.113, h-index: 8)
acta ethologica     Hybrid Journal   (Followers: 4, SJR: 0.465, h-index: 23)
Acta Geochimica     Hybrid Journal   (Followers: 6)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 2, SJR: 0.294, h-index: 13)
Acta Geotechnica     Hybrid Journal   (Followers: 7, SJR: 1.818, h-index: 22)
Acta Informatica     Hybrid Journal   (Followers: 5, SJR: 0.524, h-index: 32)
Acta Mathematica     Hybrid Journal   (Followers: 11, SJR: 8.021, h-index: 47)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2, SJR: 0.53, h-index: 29)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 6, SJR: 0.406, h-index: 30)
Acta Mathematica Vietnamica     Hybrid Journal   (SJR: 0.451, h-index: 5)
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal   (SJR: 0.22, h-index: 20)
Acta Mechanica     Hybrid Journal   (Followers: 20, SJR: 0.898, h-index: 52)
Acta Mechanica Sinica     Hybrid Journal   (Followers: 5, SJR: 0.426, h-index: 29)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5, SJR: 0.525, h-index: 18)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.524, h-index: 14)
Acta Neurochirurgica     Hybrid Journal   (Followers: 6, SJR: 0.833, h-index: 73)
Acta Neurologica Belgica     Hybrid Journal   (Followers: 1, SJR: 0.348, h-index: 27)
Acta Neuropathologica     Hybrid Journal   (Followers: 5, SJR: 6.61, h-index: 117)
Acta Oceanologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 17)
Acta Parasitologica     Hybrid Journal   (Followers: 9, SJR: 0.581, h-index: 28)
Acta Physiologiae Plantarum     Hybrid Journal   (Followers: 2, SJR: 0.551, h-index: 39)
Acta Politica     Hybrid Journal   (Followers: 13, SJR: 0.658, h-index: 20)
Activitas Nervosa Superior     Hybrid Journal  
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5, SJR: 0.103, h-index: 4)
ADHD Attention Deficit and Hyperactivity Disorders     Hybrid Journal   (Followers: 22, SJR: 0.871, h-index: 15)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 8)
Administration and Policy in Mental Health and Mental Health Services Research     Partially Free   (Followers: 15, SJR: 0.795, h-index: 40)
Adsorption     Hybrid Journal   (Followers: 4, SJR: 0.774, h-index: 52)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 3, SJR: 0.319, h-index: 15)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 34, SJR: 0.959, h-index: 44)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15, SJR: 1.255, h-index: 44)
Advances in Contraception     Hybrid Journal   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 51, SJR: 1.113, h-index: 14)
Advances in Gerontology     Partially Free   (Followers: 8, SJR: 0.141, h-index: 3)
Advances in Health Sciences Education     Hybrid Journal   (Followers: 23, SJR: 1.397, h-index: 42)
Advances in Manufacturing     Hybrid Journal   (Followers: 3, SJR: 0.2, h-index: 4)
Advances in Polymer Science     Hybrid Journal   (Followers: 41, SJR: 0.637, h-index: 89)
Advances in Therapy     Hybrid Journal   (Followers: 5, SJR: 0.79, h-index: 44)
Aegean Review of the Law of the Sea and Maritime Law     Hybrid Journal   (Followers: 7)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2, SJR: 0.882, h-index: 23)
Aerobiologia     Hybrid Journal   (Followers: 2, SJR: 0.511, h-index: 36)
Aesthetic Plastic Surgery     Hybrid Journal   (Followers: 9, SJR: 0.821, h-index: 49)
African Archaeological Review     Hybrid Journal   (Followers: 15, SJR: 0.612, h-index: 24)
Afrika Matematika     Hybrid Journal   (Followers: 1, SJR: 0.248, h-index: 6)
AGE     Hybrid Journal   (Followers: 7, SJR: 1.358, h-index: 33)
Ageing Intl.     Hybrid Journal   (Followers: 7, SJR: 0.337, h-index: 10)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
Aging Clinical and Experimental Research     Hybrid Journal   (Followers: 3, SJR: 0.529, h-index: 55)
Agricultural Research     Hybrid Journal   (Followers: 3)
Agriculture and Human Values     Hybrid Journal   (Followers: 13, SJR: 1.197, h-index: 49)
Agroforestry Systems     Hybrid Journal   (Followers: 19, SJR: 0.64, h-index: 56)
Agronomy for Sustainable Development     Hybrid Journal   (Followers: 10, SJR: 1.732, h-index: 59)
AI & Society     Hybrid Journal   (Followers: 6, SJR: 0.171, h-index: 19)
AIDS and Behavior     Hybrid Journal   (Followers: 13, SJR: 2.006, h-index: 71)
Air Quality, Atmosphere & Health     Hybrid Journal   (Followers: 4, SJR: 0.706, h-index: 19)
Akupunktur & Aurikulomedizin     Full-text available via subscription   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 4, SJR: 0.566, h-index: 18)
Algebra Universalis     Hybrid Journal   (Followers: 2, SJR: 0.388, h-index: 22)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1, SJR: 0.868, h-index: 20)
Algorithmica     Hybrid Journal   (Followers: 8, SJR: 0.898, h-index: 56)
Allergo J.     Full-text available via subscription   (Followers: 1, SJR: 0.183, h-index: 20)
Allergo J. Intl.     Hybrid Journal   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 5, SJR: 0.729, h-index: 20)
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 3, SJR: 1.392, h-index: 32)
AMBIO     Hybrid Journal   (Followers: 15, SJR: 1.094, h-index: 87)
American J. of Cardiovascular Drugs     Hybrid Journal   (Followers: 15, SJR: 0.864, h-index: 39)
American J. of Community Psychology     Hybrid Journal   (Followers: 24, SJR: 1.237, h-index: 83)
American J. of Criminal Justice     Hybrid Journal   (Followers: 8, SJR: 0.634, h-index: 13)
American J. of Cultural Sociology     Hybrid Journal   (Followers: 14, SJR: 0.283, h-index: 3)
American J. of Dance Therapy     Hybrid Journal   (Followers: 4, SJR: 0.175, h-index: 13)
American J. of Potato Research     Hybrid Journal   (Followers: 2, SJR: 0.558, h-index: 35)
American J. of Psychoanalysis     Hybrid Journal   (Followers: 22, SJR: 0.293, h-index: 13)
American Sociologist     Hybrid Journal   (Followers: 14, SJR: 0.18, h-index: 13)
Amino Acids     Hybrid Journal   (Followers: 8, SJR: 1.362, h-index: 83)
AMS Review     Partially Free   (Followers: 4)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7, SJR: 0.21, h-index: 37)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 3, SJR: 0.665, h-index: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Analysis of Verbal Behavior     Hybrid Journal   (Followers: 5)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 30, SJR: 1.096, h-index: 123)
Anatomical Science Intl.     Hybrid Journal   (Followers: 2, SJR: 0.301, h-index: 26)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3, SJR: 2.212, h-index: 69)
Animal Cognition     Hybrid Journal   (Followers: 16, SJR: 1.122, h-index: 55)
Annales françaises de médecine d'urgence     Hybrid Journal   (Followers: 1, SJR: 0.156, h-index: 4)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3, SJR: 1.377, h-index: 32)
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annali dell'Universita di Ferrara     Hybrid Journal   (SJR: 0.504, h-index: 14)
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1, SJR: 1.167, h-index: 26)
Annals of Behavioral Medicine     Hybrid Journal   (Followers: 11, SJR: 2.112, h-index: 98)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18, SJR: 1.182, h-index: 94)
Annals of Combinatorics     Hybrid Journal   (Followers: 3, SJR: 0.849, h-index: 15)
Annals of Data Science     Hybrid Journal   (Followers: 11)
Annals of Dyslexia     Hybrid Journal   (Followers: 10, SJR: 0.857, h-index: 40)
Annals of Finance     Hybrid Journal   (Followers: 28, SJR: 0.686, h-index: 14)
Annals of Forest Science     Hybrid Journal   (Followers: 6, SJR: 0.929, h-index: 57)
Annals of Global Analysis and Geometry     Hybrid Journal   (Followers: 1, SJR: 1.136, h-index: 23)
Annals of Hematology     Hybrid Journal   (Followers: 14, SJR: 1.117, h-index: 62)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 7, SJR: 0.593, h-index: 42)
Annals of Microbiology     Hybrid Journal   (Followers: 10, SJR: 0.402, h-index: 26)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 5, SJR: 0.68, h-index: 45)
Annals of Operations Research     Hybrid Journal   (Followers: 10, SJR: 1.186, h-index: 78)
Annals of Ophthalmology     Hybrid Journal   (Followers: 12)
Annals of Regional Science     Hybrid Journal   (Followers: 8, SJR: 0.405, h-index: 42)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annals of Solid and Structural Mechanics     Hybrid Journal   (Followers: 10, SJR: 0.553, h-index: 8)
Annals of Surgical Oncology     Hybrid Journal   (Followers: 14, SJR: 1.902, h-index: 127)
Annals of Telecommunications     Hybrid Journal   (Followers: 7, SJR: 0.315, h-index: 25)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1, SJR: 0.931, h-index: 31)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5, SJR: 0.992, h-index: 87)
Apidologie     Hybrid Journal   (Followers: 4, SJR: 1.14, h-index: 57)
APOPTOSIS     Hybrid Journal   (Followers: 8, SJR: 1.554, h-index: 87)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2, SJR: 0.354, h-index: 27)
Applications of Mathematics     Hybrid Journal   (Followers: 1, SJR: 0.274, h-index: 20)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 42, SJR: 0.575, h-index: 80)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 16, SJR: 0.267, h-index: 26)
Applied Cancer Research     Open Access  
Applied Categorical Structures     Hybrid Journal   (Followers: 2, SJR: 0.361, h-index: 21)
Applied Composite Materials     Hybrid Journal   (Followers: 48, SJR: 0.705, h-index: 35)
Applied Entomology and Zoology     Partially Free   (Followers: 3, SJR: 0.554, h-index: 34)
Applied Geomatics     Hybrid Journal   (Followers: 3, SJR: 0.323, h-index: 9)
Applied Geophysics     Hybrid Journal   (Followers: 8, SJR: 0.541, h-index: 13)
Applied Intelligence     Hybrid Journal   (Followers: 11, SJR: 0.777, h-index: 43)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4, SJR: 0.358, h-index: 34)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 4, SJR: 0.955, h-index: 33)
Applied Mathematics - A J. of Chinese Universities     Hybrid Journal   (SJR: 0.275, h-index: 8)
Applied Mathematics and Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.37, h-index: 26)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 61, SJR: 1.262, h-index: 161)
Applied Physics A     Hybrid Journal   (Followers: 7, SJR: 0.535, h-index: 121)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 23, SJR: 0.983, h-index: 104)
Applied Psychophysiology and Biofeedback     Hybrid Journal   (Followers: 8, SJR: 0.677, h-index: 47)
Applied Research in Quality of Life     Hybrid Journal   (Followers: 11, SJR: 0.288, h-index: 15)
Applied Solar Energy     Hybrid Journal   (Followers: 17, SJR: 0.251, h-index: 6)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4, SJR: 0.351, h-index: 9)
Aquaculture Intl.     Hybrid Journal   (Followers: 22, SJR: 0.613, h-index: 40)
Aquarium Sciences and Conservation     Hybrid Journal   (Followers: 1)
Aquatic Ecology     Hybrid Journal   (Followers: 32, SJR: 0.646, h-index: 44)
Aquatic Geochemistry     Hybrid Journal   (Followers: 4, SJR: 0.764, h-index: 39)
Aquatic Sciences     Hybrid Journal   (Followers: 13, SJR: 1.172, h-index: 53)
Arabian J. for Science and Engineering     Hybrid Journal   (Followers: 5, SJR: 0.345, h-index: 20)
Arabian J. of Geosciences     Hybrid Journal   (Followers: 1, SJR: 0.417, h-index: 16)
Archaeological and Anthropological Sciences     Hybrid Journal   (Followers: 23, SJR: 1.056, h-index: 15)
Archaeologies     Hybrid Journal   (Followers: 12, SJR: 0.397, h-index: 13)
Archiv der Mathematik     Hybrid Journal   (Followers: 1, SJR: 0.597, h-index: 29)
Archival Science     Hybrid Journal   (Followers: 56, SJR: 0.804, h-index: 22)
Archive for History of Exact Sciences     Hybrid Journal   (Followers: 8, SJR: 0.28, h-index: 15)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 1, SJR: 0.946, h-index: 23)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (SJR: 4.091, h-index: 66)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5, SJR: 0.865, h-index: 40)
Archives and Museum Informatics     Hybrid Journal   (Followers: 135)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4, SJR: 2.841, h-index: 40)
Archives of Dermatological Research     Hybrid Journal   (Followers: 7, SJR: 0.9, h-index: 65)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 11, SJR: 0.846, h-index: 84)
Archives of Gynecology and Obstetrics     Hybrid Journal   (Followers: 17, SJR: 0.695, h-index: 47)
Archives of Microbiology     Hybrid Journal   (Followers: 8, SJR: 0.702, h-index: 85)
Archives of Orthopaedic and Trauma Surgery     Hybrid Journal   (Followers: 8, SJR: 1.039, h-index: 56)
Archives of Osteoporosis     Hybrid Journal   (Followers: 2, SJR: 1.092, h-index: 13)
Archives of Sexual Behavior     Hybrid Journal   (Followers: 9, SJR: 1.198, h-index: 74)
Archives of Toxicology     Hybrid Journal   (Followers: 16, SJR: 1.595, h-index: 76)
Archives of Virology     Hybrid Journal   (Followers: 5, SJR: 1.086, h-index: 90)
Archives of Women's Mental Health     Hybrid Journal   (Followers: 14, SJR: 1.264, h-index: 50)
Archivio di Ortopedia e Reumatologia     Hybrid Journal  
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2, SJR: 1.2, h-index: 42)
ArgoSpine News & J.     Hybrid Journal   (SJR: 0.102, h-index: 3)
Argumentation     Hybrid Journal   (Followers: 5, SJR: 0.295, h-index: 18)
Arid Ecosystems     Hybrid Journal   (Followers: 3)
Arkiv för Matematik     Hybrid Journal   (Followers: 1, SJR: 0.948, h-index: 22)
Arnold Mathematical J.     Hybrid Journal   (Followers: 1)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 2, SJR: 0.797, h-index: 17)
Arthroskopie     Hybrid Journal   (Followers: 1, SJR: 0.145, h-index: 8)
Artificial Intelligence and Law     Hybrid Journal   (Followers: 10, SJR: 0.288, h-index: 25)
Artificial Intelligence Review     Hybrid Journal   (Followers: 14, SJR: 0.948, h-index: 48)
Artificial Life and Robotics     Hybrid Journal   (Followers: 8, SJR: 0.231, h-index: 14)
Asia Europe J.     Hybrid Journal   (Followers: 5, SJR: 0.247, h-index: 9)
Asia Pacific Education Review     Hybrid Journal   (Followers: 12, SJR: 0.371, h-index: 17)
Asia Pacific J. of Management     Hybrid Journal   (Followers: 16, SJR: 1.676, h-index: 50)
Asia-Pacific Education Researcher     Hybrid Journal   (Followers: 12, SJR: 0.353, h-index: 13)
Asia-Pacific Financial Markets     Hybrid Journal   (Followers: 2, SJR: 0.19, h-index: 15)
Asia-Pacific J. of Atmospheric Sciences     Hybrid Journal   (Followers: 20, SJR: 1.006, h-index: 14)
Asian Business & Management     Hybrid Journal   (Followers: 8, SJR: 0.41, h-index: 10)
Asian J. of Business Ethics     Hybrid Journal   (Followers: 7)
Asian J. of Criminology     Hybrid Journal   (Followers: 5, SJR: 0.263, h-index: 8)
AStA Advances in Statistical Analysis     Hybrid Journal   (Followers: 2, SJR: 0.681, h-index: 15)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5, SJR: 0.195, h-index: 5)
ästhetische dermatologie & kosmetologie     Full-text available via subscription  

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Journal Cover Analytical and Bioanalytical Chemistry
  [SJR: 1.096]   [H-I: 123]   [30 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1618-2650 - ISSN (Online) 1618-2642
   Published by Springer-Verlag Homepage  [2354 journals]
  • Hydrophilic magnetic ionic liquid for magnetic headspace single-drop
           microextraction of chlorobenzenes prior to thermal desorption-gas
           chromatography-mass spectrometry
    • Authors: Elena Fernández; Lorena Vidal; Antonio Canals
      Abstract: A new, fast, easy to handle, and environmentally friendly magnetic headspace single-drop microextraction (Mag-HS-SDME) based on a magnetic ionic liquid (MIL) as an extractant solvent is presented. A small drop of the MIL 1-ethyl-3-methylimidazolium tetraisothiocyanatocobaltate(II) ([Emim]2[Co(NCS)4]) is located on one end of a small neodymium magnet to extract nine chlorobenzenes (1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene, and pentachlorobenzene) as model analytes from water samples prior to thermal desorption-gas chromatography-mass spectrometry determination. A multivariate optimization strategy was employed to optimize experimental parameters affecting Mag-HS-SDME. The method was evaluated under optimized extraction conditions (i.e., sample volume, 20 mL; MIL volume, 1 μL; extraction time, 10 min; stirring speed, 1500 rpm; and ionic strength, 15% NaCl (w/v)), obtaining a linear response from 0.05 to 5 μg L−1 for all analytes. The repeatability of the proposed method was evaluated at 0.7 and 3 μg L−1 spiking levels and coefficients of variation ranged between 3 and 18% (n = 3). Limits of detection were in the order of nanograms per liter ranging from 4 ng L−1 for 1,4-dichlorobenzene and 1,2,3,4-tetrachlorobenzene to 8 ng L−1 for 1,2,4,5-tetrachlorobenzene. Finally, tap water, pond water, and wastewater were selected as real water samples to assess the applicability of the method. Relative recoveries varied between 82 and 114% showing negligible matrix effects. Graphical abstract Magnetic headspace single-drop microextraction followed by thermal desorption-gas chromatography-mass spectrometry
      PubDate: 2017-11-23
      DOI: 10.1007/s00216-017-0755-2
       
  • The scope of Analytical and Bioanalytical Chemistry (ABC)
    • Authors: H. Cui; P. Garrigues; G. Gauglitz; E. Hilder; G. Hopfgartner; D. C. Muddiman; A. Roda; A. Sanz-Medel; S. A. Wise; A. T. Woolley; L. Zhang
      PubDate: 2017-11-22
      DOI: 10.1007/s00216-017-0743-6
       
  • Multi-isotope calibration for inductively coupled plasma mass spectrometry
    • Authors: Alex Virgilio; Joaquim A. Nóbrega; George L. Donati
      Abstract: Multi-isotope calibration (MICal) is a novel approach to calibration for inductively coupled plasma mass spectrometry (ICP-MS). In MICal, only two calibration solutions are required: solution A, composed of 50% v v−1 of sample and 50% v v−1 of a standard solution containing the analytes, and solution B, composed of 50% v v−1 of sample and 50% v v−1 of a blank solution. MICal is based on monitoring the signal intensities of several isotopes of the same analyte in solutions A and B. By plotting the analytical signals from solution A in the x-axis, and from solution B in the y-axis, the analyte concentration in the sample is calculated using the slope of that graph and the concentration of the reference standard added to solution A. As both solutions contain the same amount of sample, matrix-matching is easily achieved. In this proof-of-concept study, MICal was applied to the determination of Ba, Cd, Se, Sn, and Zn in seven certified reference materials with different matrices (e.g., plant materials, flours, and water). In most cases, MICal results presented no statistical difference from the certified values at a 95% confidence level. The new strategy was also compared with traditional calibration methods such as external calibration, internal standardization and standard additions, and recoveries were generally better for MICal. This is a simple, accurate, and fast alternative method for matrix-matching calibration in ICP-MS. Graphical abstract Multi-isotope calibration: fast and innovative matrix-matching calibration for ICP-MS.
      PubDate: 2017-11-22
      DOI: 10.1007/s00216-017-0753-4
       
  • Novel comprehensive multidimensional liquid chromatography approach for
           elucidation of the microbosphere of shikimate-producing Escherichia coli
           SP1.1/pKD15.071 strain
    • Authors: Francesco Cacciola; Domenica Mangraviti; Francesca Rigano; Paola Donato; Paola Dugo; Luigi Mondello; Hernan J. Cortes
      Abstract: Shikimic acid is a intermediate of aromatic amino acid biosynthesis and the preferred starting material for production of the most commonly prescribed anti-influenza drug, Tamiflu. Its six-membered carbocyclic ring is adorned with several chiral centers and various functionalities, making shikimic acid a valuable chiral synthon. When microbially-produced, in addition to shikimic acid, numerous other metabolites are exported out of the cytoplasm and accumulate in the culture medium. This extracellular matrix of metabolites is referred to as the microbosphere. Due to the high sample complexity, in this study, the microbosphere of shikimate-producing Escherichia coli SP1.1/pKD15.071 was analyzed by liquid chromatography and comprehensive two-dimensional liquid chromatography coupled to photodiode array and mass spectrometry detection. GC analysis of the trimethylsilyl derivatives was also carried out in order to support the elucidation of the selected metabolites in the microbosphere. The elucidation of the metabolic fraction of this bacterial strain might be of valid aid for improving, through genetic changes, the concentration and yield of shikimic acid synthesized from glucose. Graphical abstract
      PubDate: 2017-11-22
      DOI: 10.1007/s00216-017-0744-5
       
  • Study on oligomerization of glutamate decarboxylase from Lactobacillus
           brevis using asymmetrical flow field-flow fractionation (AF4) with light
           scattering techniques
    • Authors: Jaeyeong Choi; Seungho Lee; Javier A. Linares-Pastén; Lars Nilsson
      Abstract: In this work, asymmetrical flow field-flow fractionation (AF4) coupled with UV/Vis, multi-angle light scattering (MALS), and differential refractive index (dRI) detectors (AF4-UV-MALS-dRI) was employed for analysis of glutamate decarboxylase (LbGadB) from Lactobacillus brevis (L. brevis). AF4 provided molecular weight (MW) (or size)-based separation of dimer, hexamer, and aggregates of LbGadB. The effect of pH on oligomerization of LbGadB was investigated, and then AF4 results were compared to those from molecular modeling. The MWs measured by AF4-UV-MALS-dRI for dimeric and hexameric forms of LbGadB were 110 and 350 kDa, respectively, which are in good agreements with those theoretically calculated (110 and 330 kDa). The molecular sizes determined by AF4-UV-MALS-dRI were also in good agreement with those obtained from molecular modeling (6 and 10 nm, respectively, for dimeric and hexameric from AF4-UV-MALS-dRI and 6.4 × 7.6 and 7.6 × 13.1 nm from molecular modeling). The effects of temperature, salt type, and salt concentration on oligomerization of LbGadB were also investigated using dynamic light scattering (DLS). It was found that the hexameric form of LbGadB was most stable at pH 6 and in presence of NaCl or KCl. The results indicate that AF4, in combination of various online detectors mentioned above, provides an effective tool for monitoring of oligomerization of LbGadB under different conditions, such as temperature, pH, type of salts, and salt concentrations.
      PubDate: 2017-11-22
      DOI: 10.1007/s00216-017-0735-6
       
  • Potential of dynamically harmonized Fourier transform ion cyclotron
           resonance cell for high-throughput metabolomics fingerprinting: control of
           data quality
    • Authors: Baninia Habchi; Sandra Alves; Delphine Jouan-Rimbaud Bouveresse; Brice Appenzeller; Alain Paris; Douglas N. Rutledge; Estelle Rathahao-Paris
      Abstract: Due to the presence of pollutants in the environment and food, the assessment of human exposure is required. This necessitates high-throughput approaches enabling large-scale analysis and, as a consequence, the use of high-performance analytical instruments to obtain highly informative metabolomic profiles. In this study, direct introduction mass spectrometry (DIMS) was performed using a Fourier transform ion cyclotron resonance (FT-ICR) instrument equipped with a dynamically harmonized cell. Data quality was evaluated based on mass resolving power (RP), mass measurement accuracy, and ion intensity drifts from the repeated injections of quality control sample (QC) along the analytical process. The large DIMS data size entails the use of bioinformatic tools for the automatic selection of common ions found in all QC injections and for robustness assessment and correction of eventual technical drifts. RP values greater than 106 and mass measurement accuracy of lower than 1 ppm were obtained using broadband mode resulting in the detection of isotopic fine structure. Hence, a very accurate relative isotopic mass defect (RΔm) value was calculated. This reduces significantly the number of elemental composition (EC) candidates and greatly improves compound annotation. A very satisfactory estimate of repeatability of both peak intensity and mass measurement was demonstrated. Although, a non negligible ion intensity drift was observed for negative ion mode data, a normalization procedure was easily applied to correct this phenomenon. This study illustrates the performance and robustness of the dynamically harmonized FT-ICR cell to perform large-scale high-throughput metabolomic analyses in routine conditions. Graphical abstract Analytical performance of FT-ICR instrument equipped with a dynamically harmonized cell.
      PubDate: 2017-11-22
      DOI: 10.1007/s00216-017-0738-3
       
  • Luminol, horseradish peroxidase, and glucose oxidase ternary
           functionalized graphene oxide for ultrasensitive glucose sensing
    • Authors: Fang Li; Wenjing Ma; Jiachang Liu; Xiang Wu; Yan Wang; Jianbo He
      Abstract: Luminol, horseradish peroxidase (HRP), and glucose oxidase (GOx) ternary functionalized graphene oxide (HRP/GOx-luminol-GO) with excellent chemiluminescence (CL) activity and specific enzymatic property was prepared via a simple and general strategy for the first time. In this approach, luminol functionalized GO (luminol-GO) was prepared by gently stirring GO with luminol. Then HRP and GOx were further co-immobilized onto the surface of luminol-GO by storing HRP and GOx with luminol-GO at 4 °C overnight, to form HRP/GOx-luminol-GO bionanocomposites. The synthesized HRP/GOx-luminol-GO could react with H2O2 generated from GOx catalyzed glucose oxidization reaction, to produce strong CL emission in the presence of co-immobilized HRP. Thus, we developed an ultrasensitive, homogeneous, reagentless, selective, and simple CL sensing system for glucose detection. The resulting biosensors exhibited ultra-wide linear range from 5.0 nM to 5.0 mM, and an ultra-low detection limit of 1.2 nM, which was more than 3 orders of magnitude lower than previously reported methods. Furthermore, the sensing system was successfully applied for the detection of glucose in human blood samples.
      PubDate: 2017-11-22
      DOI: 10.1007/s00216-017-0752-5
       
  • Identification of phase-II metabolites of flavonoids by liquid
           chromatography–ion-mobility spectrometry–mass spectrometry
    • Authors: Clément Chalet; Boudewijn Hollebrands; Hans-Gerd Janssen; Patrick Augustijns; Guus Duchateau
      Abstract: Flavonoids are a class of natural compounds with a broad range of potentially beneficial health properties. They are subjected to an extensive intestinal phase-II metabolism, i.e., conjugation to glucuronic acid, sulfate, and methyl groups. Flavonoids and their metabolites can interact with drug transporters and thus interfere with drug absorption, causing food–drug interactions. The site of metabolism plays a key role in the activity, but the identification of the various metabolites remains a challenge. Here, we developed an analytical method to identify the phase-II metabolites of structurally similar flavonoids. We used liquid chromatography–ion-mobility spectrometry–mass spectrometry (LC–IMS–MS) analysis to identify phase-II metabolites of flavonols, flavones, and catechins produced by HT29 cells. We showed that IMS could bring valuable structural information on the different positional isomers of the flavonols and flavones. The position of the glucuronide moiety had a strong influence on the collision cross section (CCS) of the metabolites, with only minor contribution of hydroxyl and methyl moieties. For the catechins, fragmentation data obtained from MS/MS analysis appeared more useful than IMS to determine the structure of the metabolites, mostly due to the high number of metabolites formed. Nevertheless, CCS information as a molecular fingerprint proved to be useful to identify peaks from complex mixtures. LC–IMS–MS thus appears as a valuable tool for the identification of phase-II metabolites of flavonoids. Graphical abstract Structural identification of phase-II metabolites of flavonoids using LC-IMS-MS.
      PubDate: 2017-11-22
      DOI: 10.1007/s00216-017-0737-4
       
  • Characterization of therapeutic protein AvidinOX by an integrated
           analytical approach
    • Authors: Giuseppe Giannini; Anna Alekseeva; Annamaria Naggi; Laura Salvini; Lorenzo Tei; Rita De Santis
      Abstract: AvidinOX, the oxidized derivative of Avidin, is a chemically modified glycoprotein, being currently under clinical investigation for targeted delivery of radioactive biotin to inoperable tumors. AvidinOX is produced by 4-hydroxyazobenzene-2-carboxylic acid (HABA)-assisted sodium periodate oxidation of Avidin. The peculiar property of the periodate-generated glycol-split carbohydrate moieties to form Schiff’s bases with amino groups of the tissue proteins allows to achieve a tissue half-life of 2 weeks compared to 2 h of native Avidin. Carbohydrate oxidation, along with possible minor amino acid modifications, introduces additional microheterogeneity in the glycoprotein structure, making its characterization even more demanding than for native glycoproteins. Aiming at the elucidation of the effects of oxidation conditions on the AvidinOX protein backbone and sugars, this microheterogeneous glycoprotein derivative was characterized for the first time using a combination of different analytical methods, including colorimetric methods, mass spectrometry, hollow-fiber flow field-flow fractionation with UV and multi-angle laser scattering detection (HF5-UV-MALS), and NMR. The proposed integrated approach reveals structural features of AvidinOX relevant for its biological activity, e.g., oxidized sites within both carbohydrate moieties and protein backbone and conformational stability, and will be considered as an analytical tool for AvidinOX industrial preparations. It is worth noting that this study enriches also the structural data of native Avidin published up-to-date (e.g., glycan structure and distribution, peptide fingerprint, etc.). Graphical abstract Scheme of phenylacetic hydrazide/MALDI-TOF approach for quantification of aldehydes in AvidinOX based on the determination of the number of hydrazone adducts between hydrazide reagent and aldehyde groups of protein
      PubDate: 2017-11-22
      DOI: 10.1007/s00216-017-0754-3
       
  • Analysis of bronopol (2-bromo-2-nitropropan-1, 3-diol) residues in rice (
           Oryza sativa L.) by SPE using Bond Elut Plexa and liquid
           chromatography-tandem mass spectrometry
    • Authors: Shuang-shuang Chai; Mei-ling Qin; You-ning Ma; Huan-huan Gao; Qiao He; Han-tong Zhang
      Abstract: A novel method has been developed for the direct, sensitive, and rapid detection of bronopol in rice using a simple solid-phase extraction (SPE) procedure followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), with electrospray ionization (ESI). Bronopol was stable under acidic conditions, and an acidic environment was thus needed before sample loading to ensure the stability of bronopol. Rice extracts containing bronopol were pretreated using a hydrophilic-lipophilic balanced (Bond Elut Plexa) cartridge to reduce the matrix effect. An XDB-C18 column (150 mm × 2.1 mm, 3.5 μm) was used for chromatographic separations, with a mobile phase comprising methanol and aqueous ammonium formate (5 mM). The linearity of the method was satisfactory with regression coefficient (R 2) = 0.9992. The limit of quantification was 3.3 μg kg−1. Three spiked levels (25, 125 and 625 μg kg−1) were used to determine the recovery of bronopol, which was found to be 73.3–96.7%, with relative standard deviations (RSD) in the range 1.2–7.9%. The RSD for intra-day precision (n = 7) was 7.6% and the RSD for inter-day precision (n = 15) was 8.3%. The newly developed analytical method was successfully used to quantify bronopol in rice samples.
      PubDate: 2017-11-21
      DOI: 10.1007/s00216-017-0730-y
       
  • Monitoring of post-mortem changes of saliva N-glycosylation by nano LC/MS
    • Authors: Bum Jin Kim; Chanyoung Han; Hantae Moon; Joseph Kwon; Ik-Soon Jang; Si-Keun Lim; Ki-Won Park; Jong-Soon Choi; Hyun Joo An
      Abstract: The estimation of post-mortem interval (PMI) is a crucial part for investigations of crime and untimely deaths in forensic science. However, standard methods of PMI estimation are easily confounded by extenuating circumstances and/or environmental factors. Therefore, a panel of PMI markers obtained from a more acceptable and accurate method is necessary to definitely determine time of death. Saliva, one of the vital fluids encountered at crime scenes, contains various glycoproteins that are highly affected by biochemical environment. Here, we investigated saliva N-glycans between live and dead rats to determine the alteration of N-glycans using an animal model system because of the limitation of saliva collection from recently deceased humans. Rat saliva samples were collected both before and after death. N-Glycans were enzymatically released by PNGase F without any glycoprotein extraction. Released native glycans were purified and enriched by PGC-SPE. About 100 N-glycans were identified, profiled, and structurally elucidated by nano LC/MS and tandem MS. Sialylated N-glycans were exclusively present in abundance in live rat saliva whereas non-sialylated N-glycans including LacdiNAc disaccharides were detected in high level following death. Through in-depth investigations using quantitative comparison and statistical analysis, 14 N-glycans that significantly changed after death were identified as the potential marker candidates for PMI estimation. To the best of our knowledge, this is the first study to monitor the post-mortem changes of saliva glycosylation, with obvious forensic applications.
      PubDate: 2017-11-21
      DOI: 10.1007/s00216-017-0702-2
       
  • Monitoring enzymatic degradation of emerging contaminants using a
           chip-based robotic nano-ESI-MS tool
    • Authors: Lara F. Stadlmair; Thomas Letzel; Johanna Graßmann
      Abstract: Up to now, knowledge of enzymes capable of degrading various contaminants of emerging concern (CEC) is limited, which is especially due to the lack of rapid screening methods. Thus, a miniaturized high-throughput setup using a chip-based robotic nanoelectrospray ionization system coupled to mass spectrometry has been developed to rapidly screen enzymatic reactions with environmentally relevant CECs. Three laccases, two tyrosinases, and two peroxidases were studied for their ability to transform ten pharmaceuticals and benzotriazole. Acetaminophen was most susceptible to enzymatic conversion by horseradish peroxidase (HRP), laccase from Trametes versicolor (LccTV), and a tyrosinase from Agaricus bisporus (TyrAB). Diclofenac and mefenamic acid were converted by HRP and LccTV, whereas sotalol was solely amenable to HRP conversion. Benzotriazole, carbamazepine, gabapentin, metoprolol, primidone, sulfamethoxazole, and venlafaxine remained persistent in this study. The results obtained here emphasize that enzymes are highly selective catalysts and more effort is required in the use of fast monitoring technologies to find suitable enzyme systems. Despite the methodological limitations discussed in detail, the automated tool provides a routine on-line screening of various enzymatic reactions to identify potential enzymes that degrade CECs. Graphical abstract A chip-based robotic nano-ESI-MS tool to rapidly monitor enzymatic degradation of environmentally relevant emerging contaminants
      PubDate: 2017-11-17
      DOI: 10.1007/s00216-017-0729-4
       
  • Single cell versus large population analysis: cell variability in
           elemental intracellular concentration and distribution
    • Authors: Emil Malucelli; Alessandra Procopio; Michela Fratini; Alessandra Gianoncelli; Andrea Notargiacomo; Lucia Merolle; Azzurra Sargenti; Sara Castiglioni; Concettina Cappadone; Giovanna Farruggia; Marco Lombardo; Stefano Lagomarsino; Jeanette A. Maier; Stefano Iotti
      Abstract: The quantification of elemental concentration in cells is usually performed by analytical assays on large populations missing peculiar but important rare cells. The present article aims at comparing the elemental quantification in single cells and cell population in three different cell types using a new approach for single cells elemental analysis performed at sub-micrometer scale combining X-ray fluorescence microscopy and atomic force microscopy. The attention is focused on the light element Mg, exploiting the opportunity to compare the single cell quantification to the cell population analysis carried out by a highly Mg-selective fluorescent chemosensor. The results show that the single cell analysis reveals the same Mg differences found in large population of the different cell strains studied. However, in one of the cell strains, single cell analysis reveals two cells with an exceptionally high intracellular Mg content compared with the other cells of the same strain. The single cell analysis allows mapping Mg and other light elements in whole cells at sub-micrometer scale. A detailed intensity correlation analysis on the two cells with the highest Mg content reveals that Mg subcellular localization correlates with oxygen in a different fashion with respect the other sister cells of the same strain. Graphical abstract Single cells or large population analysis this is the question!
      PubDate: 2017-11-17
      DOI: 10.1007/s00216-017-0725-8
       
  • Sensitive mass spectrometric assay for determination of 15-deoxy-Δ 12,14
           -prostaglandin J 2 and its application in human plasma samples of patients
           with diabetes
    • Authors: Jakob Morgenstern; Thomas Fleming; Ivelina Kadiyska; Sebastian Brings; Jan Benedikt Groener; Peter Nawroth; Markus Hecker; Maik Brune
      Abstract: The determination of individual prostaglandins (PG) in humans is mainly performed in urine samples. The quantification of PGs in human plasma could improve the understanding of particular PG species under various physiological and pathological conditions. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) is a dehydrated downstream product of PGD2 and is of high interest due to its recently discovered anti-inflammatory effects. Increasing availability of highly sensitive mass spectrometry allows the quantification of low abundant biomarkers like 15d-PGJ2 in human plasma samples. Herein, a sensitive LC-MS/MS method for the determination of 15d-PGJ2 was established. The method was validated according to the guidance of the American Food and Drug Administration and tested in plasma samples from patients with poorly controlled diabetes, considered to be a pro-inflammatory condition. Extraction of 15d-PGJ2 was achieved with an easy-to-use liquid-liquid extraction by ethyl acetate following a methanol precipitation. The lower limit of quantification was 2.5 pg mL−1 and linearity (R 2 = 0.998) was guaranteed between 2.5 and 500 pg mL−1 for 15d-PGJ2. Selectivity was assured by the use of two individual mass transitions (qualifier and quantifier). Precision and accuracy were validated in an inter- and intraday assay with a coefficient of variation below 11.8% (intraday) and 14.7% (interday). In diabetic patients with an HbA1C > 9%, increased plasma concentrations of 15d-PGJ2 compared to control plasma were measured. 15d-PGJ2 correlated negatively with the inflammation marker C-reactive protein. The developed LC-MS/MS method represents a new possibility to quantify 15d-PGJ2 with high specificity in human plasma samples. This may contribute to a better understanding of the potential anti-inflammatory effects of 15d-PGJ2 in severe long-term pro-inflammatory disorders like diabetes, cancer, or cardiovascular disease.
      PubDate: 2017-11-16
      DOI: 10.1007/s00216-017-0748-1
       
  • Graphene quantum dots–terbium ions as novel sensitive and selective
           time-resolved luminescent probes
    • Authors: Eulogio J. Llorent-Martínez; Gema M. Durán; Ángel Ríos; Antonio Ruiz-Medina
      Abstract: We propose an alternative approach for the development of analytical methods based on terbium-sensitized luminescence (TSL). TSL is based on the complexation between Tb(III) ions and fluorescent organic compounds that have appropriate functional groups to complex with Tb(III). We report the use of graphene quantum dot (GQDs) nanoparticles to improve the sensitivity and selectivity of TSL detection. GQDs can react with terbium ions through the carboxylic groups present in their structure. These Tb(III)–GQD complexes, formed in situ in aqueous solution, can be used as time-resolved luminescent probes. Ascorbic acid was selected as a target analyte to demonstrate the suitability of the proposed method. The selectivity of the TSL method was highly improved for most of the interferences tested. Under the optimum conditions [Tb(III) concentration 5 × 10-4 mol L-1, GQD concentration 4 mg L-1], a minimum 100% increase in selectivity was observed for several vitamins and common cations that may be present in the samples to be analyzed. In addition, the analytical signal showed a 30% enhancement with the use of GQDs compared with the use of merely Tb(III) ions, with a detection limit of 0.12 μg mL-1. The repeatability and intermediate precision were lower than 3% and 5%, respectively. From the results obtained, the implementation of GQDs in TSL can lead to the development of novel time-resolved luminescent probes with high analytical potential. Graphical abstract Quenching of Tb(III)–graphene quantum dot (GQD) luminescence by ascorbic acid (AA). TBL terbium-sensitized luminescence
      PubDate: 2017-11-16
      DOI: 10.1007/s00216-017-0728-5
       
  • Steroid hormone profiling in human breast adipose tissue using
           semi-automated purification and highly sensitive determination of
           estrogens by GC-APCI-MS/MS
    • Authors: Kristin Hennig; Jean Philippe Antignac; Emmanuelle Bichon; Marie-Line Morvan; Isabelle Miran; Suzette Delaloge; Jean Feunteun; Bruno Le Bizec
      Abstract: Body mass index is a known breast cancer risk factor due to, among other mechanisms, adipose-derived hormones. We developed a method for steroid hormone profiling in adipose tissue to evaluate healthy tissue around the tumor and define new biomarkers for cancer development. A semi-automated sample preparation method based on gel permeation chromatography and subsequent derivatization with trimethylsilyl (TMS) is presented. Progestagens and androgens were determined by GC-EI-MS/MS (LOQ 0.5 to 10 ng/g lipids). For estrogen measurement, a highly sensitive GC-APCI-MS/MS method was developed to reach the required lower limits of detection (0.05 to 0.1 ng/g lipids in matrix, 100–200 fg on column for pure standards). The combination of the two methods allows the screening of 27 androgens and progestagens and 4 estrogens from a single sample. Good accuracies and repeatabilities were achieved for each compound class at their respective limit of detection. The method was applied to determine steroid hormone profiles in adipose tissue of 51 patients, collected both at proximity and distant to the tumor. Out of the 31 tested steroid hormones, 14 compounds were detected in human samples. Pregnenolone, 17-hydroxypregnenolone, dehydroepiandrosterone (DHEA), and androstendione accounted together for 80% of the observed steroid hormone profiles, whereas the estrogens accounted for only 1%. These profiles did not differ based on sampling location, except for ß-estradiol; steroid hormone conversions from androgens to estrogens that potentially take place in adipose or tumoral tissue might not be detectable due a factor 100 difference in concentration of for example DHEA and ß-estradiol. Graphical Schematic overview of the determination of steroid hormones and metabolites in adipose tissue in proximity and distal to the tumor
      PubDate: 2017-11-16
      DOI: 10.1007/s00216-017-0717-8
       
  • Multianalyte, high-throughput liquid chromatography tandem mass
           spectrometry method for the sensitive determination of fungicides and
           insecticides in wine
    • Authors: Gabriela Castro; Leticia Pérez-Mayán; Tamara Rodríguez-Cabo; Isaac Rodríguez; Maria Ramil; Rafael Cela
      Abstract: Evidence of pesticide transfer from grapes to wine, added to differences in the national regulations regarding the number and the maximum concentration of these species in wine, demands analytical procedures suitable for their routine control in this foodstuff. In this research, solid-phase extraction (SPE) and ultra-performance liquid chromatography (UPLC), with tandem mass spectrometry (MS/MS) detection, are combined to obtain a sensitive and rapid procedure to determine 50 pesticides in red and white wines. Efficiency and selectivity of sample preparation are correlated with the type of sorbent, the elution solvent, and the physicochemical properties of pesticides. SPE of 2-mL wine samples followed by direct injection of the extract in the UPLC-MS/MS system provides quantification limits (LOQs) below 1 ng mL−1 for 48 out of 50 compounds, linear responses up to 200 ng mL−1, and acceptable accuracy, employing quantification against solvent-based standards, for 45 species. A total analysis time of 10 min, including compounds separation and re-equilibration of the UPLC column, was achieved. The developed methodology was applied to 25 wines (20 conventional and 5 ecological), produced in 7 different countries. Out of 27 pesticides quantified in these wines, 12 displayed occurrence frequencies above 24%; moreover, all wines, except one of the ecological ones, contained residues from at least one pesticide.
      PubDate: 2017-11-16
      DOI: 10.1007/s00216-017-0724-9
       
  • FT-MIR and NIR spectral data fusion: a synergetic strategy for the
           geographical traceability of Panax notoginseng
    • Authors: Yun Li; Jin-Yu Zhang; Yuan-Zhong Wang
      Abstract: Three data fusion strategies (low-llevel, mid-llevel, and high-llevel) combined with a multivariate classification algorithm (random forest, RF) were applied to authenticate the geographical origins of Panax notoginseng collected from five regions of Yunnan province in China. In low-level fusion, the original data from two spectra (Fourier transform mid-IR spectrum and near-IR spectrum) were directly concatenated into a new matrix, which then was applied for the classification. Mid-level fusion was the strategy that inputted variables extracted from the spectral data into an RF classification model. The extracted variables were processed by iterate variable selection of the RF model and principal component analysis. The use of high-level fusion combined the decision making of each spectroscopic technique and resulted in an ensemble decision. The results showed that the mid-level and high-level data fusion take advantage of the information synergy from two spectroscopic techniques and had better classification performance than that of independent decision making. High-level data fusion is the most effective strategy since the classification results are better than those of the other fusion strategies: accuracy rates ranged between 93% and 96% for the low-level data fusion, between 95% and 98% for the mid-level data fusion, and between 98% and 100% for the high-level data fusion. In conclusion, the high-level data fusion strategy for Fourier transform mid-IR and near-IR spectra can be used as a reliable tool for correct geographical identification of P. notoginseng. Graphical abstract The analytical steps of Fourier transform mid-IR and near-IR spectral data fusion for the geographical traceability of Panax notoginseng
      PubDate: 2017-11-16
      DOI: 10.1007/s00216-017-0692-0
       
  • Isomers of tris(chloropropyl) phosphate (TCPP) in technical mixtures and
           environmental samples
    • Authors: Jimmy W. Truong; Miriam L. Diamond; Paul A. Helm; Liisa M. Jantunen
      Abstract: Tris(chloropropyl) phosphate (TCPP) is an environmentally abundant organophosphate ester (OPE). TCPP is comprised of four isomers with seven possible structures, eight CAS numbers, and even more common names. A review of 54 studies reporting one or more TCPP isomers confirmed that the most abundant and most often reported TCPP isomer was tris(2-chloro-1-methylethyl) phosphate, also known as tris(chloroisopropyl) phosphate (TCiPP, referred to hereafter as TCPP1). Full-scan gas chromatography-mass spectrometry (GC-MS) was used to identify the other three isomers numbered here according to their elution order on a non-polar GC column (DB-5): bis(2-chloro-1-methylethyl) (2-chloropropyl) phosphate (TCPP2), bis(2-chloropropyl)(2-chloro-1-methylethyl) phosphate (TCPP3), and tris(2-chloropropyl) phosphate (TCPP4). GC with a flame ionization detector (FID) was used to identify the relative abundances of the isomers in commercially available standards with unknown isomer composition. In technical TCPP, TCPP1–4 isomers averaged 71 ± 1, 26 ± 0.4, 3 ± 0.5, and 0.1 ± 0.02%, respectively. When these percent masses are incorporated into GC-MS quantification, response factors (RFs) for TCPP1 and TCPP2 are significantly different from TCPP3 and TCPP4, indicating that the multiple RF approach is more accurate than the commonly employed single RF method. Samples from urban streams and wastewater treatment plant (WWTP) effluent from Toronto, Canada, had isomeric ratios of TCPP1/2 that were not significantly different from a technical mixture whereas rain had a significantly different ratio indicating enrichment in the more volatile TCPP1 isomer. Reporting TCPP isomers can provide insight into sources, transport, and fate of TCPP in the environment. Graphical ᅟ
      PubDate: 2017-11-16
      DOI: 10.1007/s00216-017-0572-7
       
  • Comparison of analytical tools appropriate for identification of
           proteinaceous additives in historical mortars
    • Authors: Iva Krizova; Julia Schultz; Ivan Nemec; Radomir Cabala; Radovan Hynek; Stepanka Kuckova
      Abstract: Natural organic additives such as eggs, lard, resins, and oils have been added to mortars since ancient times, because the ancient builders knew of their positive effect on the mortar quality. The tradition of adding organic materials to mortars was commonly handed down only verbally for thousands years. However, this practice disappeared in the nineteenth century, when the usage of modern materials started. Today, one of the most recent topics in the industry of building materials is the reusing of natural organic materials and searching for the forgotten ancient recipes. The research of the old technological approaches involves currently the most advanced analytical techniques and methods. This paper is focussed on testing the possibility of identification of proteinaceous additives in historical mortars and model mortar samples containing blood, bone glue, curd, eggs and gelatine, by Fourier transform infrared (FTIR) and Raman spectroscopy, gas chromatography - mass spectrometry (GC-MS), matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS), liquid chromatography-electrospray ionisation-quadrupole-time of flight mass spectrometry (LC-ESI-Q-TOF MS) and enzyme-linked immunosorbent assay (ELISA). All these methods were applied to the mortar sample taken from the interior of the medieval (sixteenth century) castle in Namest nad Oslavou in the Czech Republic and their comparison contributed to the rough estimation of the protein additive content in the mortar. The obtained results demonstrate that only LC-ESI-Q-TOF MS, MALDI-TOF MS and ELISA have the sufficiently low detection limits that enable the reliable identification of collagens in historical mortars. Graphical abstract Proteomics analyses of historical mortars
      PubDate: 2017-11-16
      DOI: 10.1007/s00216-017-0709-8
       
 
 
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