title: Glass-chip-based sample preparation and on-chip trypic digestion for matrix-assisted laser desorption/ionization mass spectrometric analysis using a sol-gel/2,5-dihydroxybenzoic acid hybrid matrix.
abstract: A glass-chip-based sample preparation method for matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) analysis of tryptic digests of proteins and intact cells is described. A MALDI matrix, 2,5-dihydroxybenzoic acid (2,5-DHB), was hybridized with sol-gels to generate a sol-gel-derived material. Taking advantage of the characteristics of sol-gels, the sol-gel-derived material readily adhered to the surface of a glass chip through covalent bonding. Only one step of sample preparation, deposition of the sample solution on the glass chip, was required before MALDI-MS analysis. Because 2,5-DHB was homogeneously dispersed on the sol-gel network structure, good spot-to-spot reproducibility was obtained in MALDI analysis using this approach and the analyte signals were uniform throughout the chip. The modified glass chips were robust and effective for at least 1 week. This glass-chip-based matrix preparation method provides a straightforward approach to developing techniques for analyzing the on-chip enzymatic digestion of proteins and intact cells of microorganisms. Cytochrome C and Escherichia coli were used as analytes to demonstrate the feasibility of this approach. The products of the on-chip enzymatic digests were identified through protein database searches.
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan.
authors.forename: Ya-Shiuan
authors.initials: YS
authors.lastname: Lin
authors.forename: Chin-Hsiung
authors.initials: CH
authors.lastname: Yang
authors.forename: Yu-Chie
authors.initials: YC
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000737:chemistry; D005782:Gels; D005841:Gentisates / Q000737:chemistry*; D005898:Glass; D008969:Molecular Sequence Data; D011506:Proteins / Q000032:analysis / Q000378:metabolism; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014357:Trypsin / Q000378:metabolism
chemical_list: D005782:Gels; D005841:Gentisates; D011506:Proteins; D014357:Trypsin; C010925:2,5-dihydroxybenzoic acid