title: Electrospray micromixer chip for on-line derivatization and kinetic studies.
abstract: 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.
authors: Laboratoire d'Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
authors: Mélanie
authors: M
authors: Abonnenc
authors: Loïc
authors: L
authors: Dayon
authors: Brice
authors: B
authors: Perruche
authors: Niels
authors: N
authors: Lion
authors: Hubert H
authors: HH
authors: Girault
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003545:Cysteine / Q000737:chemistry*; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D056656:Lab-On-A-Chip Devices; D046208:Microchip Analytical Procedures / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D008956:Models, Chemical; D010446:Peptide Fragments / Q000737:chemistry; D010455:Peptides / Q000032:analysis / Q000737:chemistry*; D010777:Photochemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods; D014357:Trypsin / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D016227:Benzoquinones; D010446:Peptide Fragments; D010455:Peptides; D012710:Serum Albumin, Bovine; D014357:Trypsin; D003545:Cysteine