Miniaturized two-dimensional capillary electrophoresis on a microchip for analysis of the tryptic digest of proteins

Yongzheng Cong, Lihua Zhang, Dingyin Tao, Yu Liang, Weibing Zhang, Yukui Zhang

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


A two-dimensional capillary electrophoresis platform, combining isoelectric focusing (IEF) and capillary zone electrophoresis (CZE), was established on a microchip with the channel width and depth as 100 μm and 40 μm, respectively. With polyacrylamide as permanent coating, EOF in the microchannel, which could impair the separation, was decreased to 3.4 × 10-9m2 · V-1 · s-1, about 1/10 of that obtained in the uncoated set-up. During the separation, peptides were first focused by IEF in the first dimensional channel, and then directly driven into the perpendicular channel by controlling the applied voltages, and separated by CZE. Effects of various experimental parameters, including the electric field strength, channel length, and injection frequency from the first to the second dimensional separation channel, were studied. Under optimized condition, the digests of BSA and proteins extracted from E. coli were separated, and a peak capacity of 540 was obtained, which was far greater than that obtained by each single dimensional separation. All these results showed the promise of multidimensional separation on a microchip for the high-throughput and high-resolution analysis of complex samples.

Original languageEnglish (US)
Pages (from-to)588-594
Number of pages7
JournalJournal of Separation Science
Issue number3
StatePublished - Feb 1 2008


  • Microchip electrophoresis
  • Peptides
  • Permanent coating
  • Separation voltage
  • Two dimensional electrophoresis

ASJC Scopus subject areas

  • Analytical Chemistry
  • Filtration and Separation


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