Article: article from journal or magazin.
Electrospray micromixer chip for on-line derivatization and kinetic studies.
Publication types: Journal Article ; Research Support, Non-U.S. Gov't Publication Status: ppublish
An electrospray microchip for mass spectrometry comprising an integrated passive mixer to carry out on-chip chemical derivatizations is described. The microchip fabricated using UV-photoablation is composed of two microchannels linked together by a liquid junction. Downstream of this liquid junction, a mixing unit made of parallel oblique grooves is integrated to the microchannel in order to create flow perturbations. Several mixer designs are evaluated. The mixer efficiency is investigated both by fluorescence study and mass spectrometric monitoring of the tagging reaction of cysteinyl peptides with 1,4-benzoquinone. The comparisons with a microchip without a mixing unit and a kinetic model are used to assess the efficiency of the mixer showing tagging kinetics close to that of bulk reactions in an ideally mixed reactor. As an ultimate application, the electrospray micromixer is implemented in a LC-MS workflow. On-line derivatization of albumin tryptic peptides after a reversed-phase separation and counting of their cysteines drastically enhance the protein identification.
Benzoquinones/chemistry, Chromatography, High Pressure Liquid/methods, Cysteine/chemistry, Image Processing, Computer-Assisted, Kinetics, Microchip Analytical Procedures/instrumentation, Microchip Analytical Procedures/methods, Microfluidic Analytical Techniques/instrumentation, Microfluidic Analytical Techniques/methods, Models, Chemical, Peptide Fragments/chemistry, Peptides/analysis, Peptides/chemistry, Photochemistry, Serum Albumin, Bovine/chemistry, Spectrometry, Mass, Electrospray Ionization/instrumentation, Spectrometry, Mass, Electrospray Ionization/methods, Trypsin/chemistry, Ultraviolet Rays
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