title: Selective protein removal and desalting using microchip CE.
abstract: This paper describes the on-line sample pretreatment and analysis of proteins and peptides with a poly(methylmethacrylate) (PMMA) microfluidic device (IonChip). This chip consists of two hyphenated electrophoresis channels with integrated conductivity detectors. The first channel can be used for sample preconcentration and sample clean-up, while in the second channel the selected compounds are separated. Isotachophoresis (ITP) combined with zone electrophoresis (CZE) was used to preconcentrate a myoglobin sample by a factor of about 65 before injection into the second dimension and to desalt a mixture of six proteins with 100 mM NaCl. However, ITP-CZE could not be used for the removal of two proteins from a protein/peptide sample since the protein zone in the ITP step was too small to remove certain compounds. Therefore, we used CZE-CZE for the removal of proteins from a protein/peptide mixture, thereby injecting only the peptides into the second CZE separation channel.
authors.affiliation: Department of Biomedical Analysis, Faculty of Pharmaceutical Sciences, Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands. l.h.h.silvertand@pharm.uu.nl
authors.forename: L H H
authors.initials: LH
authors.lastname: Silvertand
authors.forename: E
authors.initials: E
authors.lastname: Machtejevas
authors.forename: R
authors.initials: R
authors.lastname: Hendriks
authors.forename: K K
authors.initials: KK
authors.lastname: Unger
authors.forename: W P
authors.initials: WP
authors.lastname: van Bennekom
authors.forename: G J
authors.initials: GJ
authors.lastname: de Jong
mesh_terms: D000818:Animals; D046209:Electrophoresis, Microchip / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D009862:Online Systems; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D011506:Proteins