Dynamic pH junction-sweeping for on-line focusing of dipeptides in capillary electrophoresis with laser-induced fluorescence detection

Ying Chen, Lan Zhang, Zongwei CAI, Guonan Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

In this paper, we developed a simple and effective on-line focusing technique combining dynamic pH junction and sweeping by capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection. Dynamic pH junction-sweeping is defined when the sample has a different buffer pH (dynamic pH junction condition) and is devoid of micelles (sweeping condition) relative to the background electrolyte (BGE). This hyphenated focusing mode was applied to the sensitive and selective focusing of four dipeptides: Tyr-Phe, Tyr-Leu, Trp-Gly, and Ala-Gln. Picomolar detectability of these dipeptides by CE-LIF detection was demonstrated through effective focusing of large sample volumes (up to 39% capillary length) using the dual pH junction-sweeping focusing mode. 25 mmol L-1 sodium dihydrogen phosphate, pH 2.5 was used as the sample matrix, and 100 mmol L-1 borate, 21 mmol L-1 sodium dodecylsulfate (SDS), 16 mmol L-1 Brij35, pH 9.0 as the background solution (BGS). The concentration detection limits (S/N = 3) of the four dipeptides were in the range of 1.0-5.0 pmol L-1. The developed method has been successfully used for the determination of dipeptides in human serum samples.

Original languageEnglish
Pages (from-to)1852-1858
Number of pages7
JournalThe Analyst
Volume136
Issue number9
DOIs
Publication statusPublished - 7 May 2011

Scopus Subject Areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry

Fingerprint

Dive into the research topics of 'Dynamic pH junction-sweeping for on-line focusing of dipeptides in capillary electrophoresis with laser-induced fluorescence detection'. Together they form a unique fingerprint.

Cite this