We describe for the first time the direct quantitative analysis of human C-peptide from urine by isotope dilution assay. Implementation of 2-D reverse phase-reverse phase chromatography (2-D RP-RP) with SIM detection resulted in high assay sensitivity (LOQ= 5 pg on column), accuracy, and method ruggedness. Our experiments demonstrate the strong resolving capability of our proposed 2-D RP-RP platform which significantly reduces strong matrix effects and their resulting quantitation error over a wide range of urine concentrations. In contrast, single column methods (both SIM and multiple reaction monitoring) were found acceptable only for strongly diluted urine samples.
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http://dx.doi.org/10.1002/jssc.200500369 | DOI Listing |
Anal Bioanal Chem
May 2020
Department of Chemistry, 102 Biosystems Research Complex, Clemson University, Clemson, SC, 29634, USA.
Online, comprehensive two-dimensional liquid chromatography (2D-LC) has become an attractive option for the analysis of complex samples of relevance in various fields (e.g., environmental, food, biology, and polymer sciences).
View Article and Find Full Text PDFJ Chromatogr A
March 2016
State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China. Electronic address:
Chinese medicine formulas represent an excellent illustration for "complex matrix". The complexity lies in a big array of small molecules with high chemical diversity. The present paper describes a novel chemical profiling solution for complex matrix by combining comprehensive and multiple heart-cutting two-dimensional liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (2DLC/qTOF-MS).
View Article and Find Full Text PDFJ Proteome Res
February 2012
Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125 Berlin, Germany.
Quantitative mass spectrometry (MS) in combination with affinity purification approaches allows for an unbiased study of protein-protein and peptide-protein interactions. In shotgun approaches that are based on proteolytic digestion of complex protein mixtures followed by two-dimensional liquid-phase chromatography, the separation effort prior to MS analysis is focused on tryptic peptides. Here we developed an improved offline 2-D liquid chromatography-MS/MS approach for the identification and quantification of binding proteins utilizing reversed-phase capillary columns with acidic acetonitrile-containing eluents in both chromatographic dimensions.
View Article and Find Full Text PDFElectrophoresis
November 2011
Department of Chemistry, The University of Hong Kong, Hong Kong, PR China.
In this paper, we describe an online combination of reversed-phase/reversed-phase (RP-RP) and porous graphitic carbon (PGC) liquid chromatography (LC) for multicomponent analysis of proteomics and glycoproteomics samples. The online RP-RP portion of this system provides comprehensive 2-D peptide separation based on sequence hydrophobicity at pH 2 and 10. Hydrophilic components (e.
View Article and Find Full Text PDFProteomics
June 2011
Department of Chemistry, The University of Hong Kong, Hong Kong, P R China.
Herein, we describe the development of a fully automatable technology that features online coupling of high-pH RP separation with conventional low-pH RP separation in a two-dimensional capillary liquid chromatography (2-D LC) system for shotgun proteomics analyses. The complete analysis comprises 13 separation cycles, each involving transfer of the eluate from the first-dimension, high-pH RP separation onto the second RP dimension for further separation. The solvent strength increases across the 13 fractions (cycles) to elute all peptides for further resolution on the second-dimension, low-pH RP separation, each under identical gradient-elution conditions.
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