The Experts below are selected from a list of 66270 Experts worldwide ranked by ideXlab platform
Matthias Mann - One of the best experts on this subject based on the ideXlab platform.
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comparison of ultrafiltration units for proteomic and n glycoproteomic analysis by the filter aided Sample Preparation Method
Analytical Biochemistry, 2011Co-Authors: Jacek R Wisniewski, Dorota F Zielinska, Matthias MannAbstract:The filter-aided Sample Preparation (FASP) Method allows gel-free processing of biological Samples solubilized with detergents for proteomic analysis by mass spectrometry. In FASP detergents are removed by ultrafiltration, and after protein digestion peptides are separated from undigested material. Here we compare the effectiveness of different filtration devices for analysis of proteomes and glycoproteomes. We show that Microcon and Vivacon filtration units with nominal molecular weight cutoffs of 30,000 and 50,000 (30 and 50 k, respectively) are equally suitable for FASP, whereas Microcon 30 k units are most appropriate for mapping of N-glycosylation sites. The use of filters with these relatively large cutoffs facilitates depletion of detergents.
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universal Sample Preparation Method for proteome analysis
Nature Methods, 2009Co-Authors: Jacek R Wisniewski, Alexandre Zougman, Nagarjuna Nagaraj, Matthias MannAbstract:We describe a Method, filter-aided Sample Preparation (FASP), which combines the advantages of in-gel and in-solution digestion for mass spectrometry-based proteomics. We completely solubilized the proteome in sodium dodecyl sulfate, which we then exchanged by urea on a standard filtration device. Peptides eluted after digestion on the filter were pure, allowing single-run analyses of organelles and an unprecedented depth of proteome coverage.
Manfred Wuhrer - One of the best experts on this subject based on the ideXlab platform.
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hydrophilic interaction chromatography based high throughput Sample Preparation Method for n glycan analysis from total human plasma glycoproteins
Analytical Chemistry, 2008Co-Authors: Renee L Ruhaak, Carolin Huhn, W J Waterreus, Arjen R De Boer, Christian Neususs, Cornelis H Hokke, Andre M Deelder, Manfred WuhrerAbstract:Many diseases are associated with changes in the glycosylation of plasma proteins. To search for glycan biomarkers, large Sample sets have to be investigated for which high-throughput Sample Preparation and analysis Methods are required. We here describe a 96 well plate-based high-throughput procedure for the rapid Preparation of 2-aminobenzoic acid (2-AA) labeled N-glycans from 10 μL of human plasma. During this procedure, N-glycans are released from glycoproteins and subsequently labeled with 2-AA without prior purification. A hydrophilic interaction chromatography (HILIC)-based solid phase extraction Method is then applied to isolate the 2-AA labeled N-glycans, which can be analyzed by MALDI-TOF-MS, HPLC with fluorescence detection, and CE−MS. The relative standard deviation for the intrabatch repeatability and the interbatch repeatability of the Sample Preparation Method remained below 7% and below 9%, respectively, for all peaks observed by HPLC. Similar results were obtained with MALDI-TOF-MS, where...
Xin Liu - One of the best experts on this subject based on the ideXlab platform.
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determination of 16 phthalate esters in tea Samples using a modified quechers Sample Preparation Method combined with gc ms ms
Food Additives and Contaminants Part A-chemistry Analysis Control Exposure & Risk Assessment, 2014Co-Authors: Peng Yin, Xin Liu, Hongping Chen, Rong PanAbstract:A modified QuEChERS Method for the determination of 16 phthalate esters (PAEs) in tea Samples using GC-MS/MS was developed and validated. The kinds and amounts of adsorbents were optimised, and the crude extracts were purified using primary secondary amine (PSA), graphitised carbon black (GCB) and anhydrous magnesium sulphate (MgSO4). Compared with extraction without matrix hydration, the addition of water could achieve higher extraction efficiency. The recoveries for PAEs obtained against matrix-matched standards at spiking levels of 50, 200 and 500 μg kg–1 ranged from 84.7% to 112.7% with relative standard deviations below 20% (n = 6) for all cases. Limits of detection (0.6–36.0 μg kg–1) and quantitation (2.0–120.0 μg kg–1) were achieved using the proposed Method for all PAEs. A total of 105 tea Samples were found to be contaminated with PAEs.
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a modified quechers Sample Preparation Method for the analysis of 70 pesticide residues in tea using gas chromatography tandem mass spectrometry
Food Analytical Methods, 2014Co-Authors: Hongping Chen, Peng Yin, Qinghua Wang, Ying Jiang, Xin LiuAbstract:A modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) Method for the simultaneous determination of 70 pesticides in tea was developed using gas chromatography-tandem mass spectrometry. Prior to acetonitrile extraction of the target compounds from tea matrix, Samples were soaked in distilled water to improve the extraction efficiency. A mixture of adsorbents containing primary–secondary amine, octadecylsilane, graphite carbon black, and multiwalled carbon nanotubes was applied for the cleanup. Additional steps of concentration and solvent exchange were performed to reduce the amount of co-extracts and to decrease the limit of detection of the Method. For all pesticides, good linear calibrations with coefficients (R2) ≥0.99 were obtained at the concentration levels of 10, or 50 to 1,000 μg ml−1. The limits of quantifications (LOQs) were 5–25 μg ml−1, respectively. The recovery rates of Samples spiked with 20, 100, and 200 μg kg−1 of analytes ranged from 71 % to 105 %. In addition, the relative standard deviations were lower than 20 %. A total of 331 tea Samples were analyzed using this Method, and the levels of five pesticide residues in nine tea Samples exceeded the strictest maximum residual limits (MRLs).
David M. Hercules - One of the best experts on this subject based on the ideXlab platform.
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MALDI-TOF MS stability study of model poly(p-phenylene terephthalamide)s.
Analytical and bioanalytical chemistry, 2009Co-Authors: Anthony P. Gies, Anton Schotman, David M. HerculesAbstract:In the present study, we address the possibility of matrix-assisted laser desorption/ionization (MALDI)–time-of-flight MS analysis-induced chain fragmentation in poly(p-phenylene terephthalamide) (PPD-T) by considering two possible sources: (1) grinding-induced fragmentation resulting from the evaporation–grinding MALDI Sample Preparation Method (E-G Method) and (2) in-source/metastable fragmentation induced by the MALDI laser. An analysis of variance (ANOVA) statistical study found, with a high probability, that obtaining MALDI spectra with the effective laser area as large as possible (the “fanned-out” setting) did not cause any chain fragmentation due to the E-G MALDI Sample Preparation Method, even when three additional grinding steps were used. However, the effect of laser fluence was less clear. A significant effect of laser fluence was observed for lower mass oligomers (
Jacek R Wisniewski - One of the best experts on this subject based on the ideXlab platform.
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comparison of ultrafiltration units for proteomic and n glycoproteomic analysis by the filter aided Sample Preparation Method
Analytical Biochemistry, 2011Co-Authors: Jacek R Wisniewski, Dorota F Zielinska, Matthias MannAbstract:The filter-aided Sample Preparation (FASP) Method allows gel-free processing of biological Samples solubilized with detergents for proteomic analysis by mass spectrometry. In FASP detergents are removed by ultrafiltration, and after protein digestion peptides are separated from undigested material. Here we compare the effectiveness of different filtration devices for analysis of proteomes and glycoproteomes. We show that Microcon and Vivacon filtration units with nominal molecular weight cutoffs of 30,000 and 50,000 (30 and 50 k, respectively) are equally suitable for FASP, whereas Microcon 30 k units are most appropriate for mapping of N-glycosylation sites. The use of filters with these relatively large cutoffs facilitates depletion of detergents.
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universal Sample Preparation Method for proteome analysis
Nature Methods, 2009Co-Authors: Jacek R Wisniewski, Alexandre Zougman, Nagarjuna Nagaraj, Matthias MannAbstract:We describe a Method, filter-aided Sample Preparation (FASP), which combines the advantages of in-gel and in-solution digestion for mass spectrometry-based proteomics. We completely solubilized the proteome in sodium dodecyl sulfate, which we then exchanged by urea on a standard filtration device. Peptides eluted after digestion on the filter were pure, allowing single-run analyses of organelles and an unprecedented depth of proteome coverage.
