Pharmaceutical Sciences Faculty Publications

On-Column Sample Enrichment for Capillary Electrophoresis Sheathless Electrospray Ionization Mass Spectrometry: Evaluation for Peptide Analysis and Protein Identification

Document Type

Article

Publication Date

11-1-2003

Journal Title

Analytical Chemistry

ISSN

0003-2700

Volume

75

Issue

21

First Page

5984

Last Page

5993

DOI

10.1021/ac0301548

PubMed ID

14588041

Abstract

Although several designs have been advanced for coupling sample enrichment devices to a sheathless electrospray ionization-mass spectrometry (MS) interface on a capillary electrophoresis (CE) column, most of these approaches suffer from difficulties in fabrication, and the CE separation efficiency is degraded as a result of the presence of coupling sleeves. We have developed a design that offers significant improvements in terms of ease of fabrication, durability, and maintenance of the integrity of the CE-separated analyte zones. Capillaries with different inside and outside diameters were evaluated to optimize the performance of the CE-MS system, resulting in a mass limit of detection of 500 amol for tandem MS analysis of a standard peptide using a 20-microm-i.d. capillary. The improved design incorporates an efficient method to preconcentrate a sample directly within the CE capillary followed by its electrophoretic separation and detection using a true zero dead-volume sheathless CE-MS interface. Testing of this novel CE-MS system showed its ability to characterize proteomic samples such as protein digests, in-gel-digested proteins, and hydrophobic peptides as well as to quantitate ICAT-labeled peptides.

Keywords

Amino acid sequence, apoproteins, bacteriorhodopsins, electrophoresis, capillary, hydrofluoric acid, isotope labeling, microscopy, electron, molecular weight, myoglobin, peptides, proteins, serum albumin, silicon dioxide, spectrometry, mass, electrospray ionization, trypsin

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