Document Type

Journal Article

Department/Unit

Department of Chemistry

Title

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

Language

English

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. © 2011 The Royal Society of Chemistry.

Publication Date

2011

Source Publication Title

Analyst

Volume

136

Issue

9

Start Page

1852

End Page

1858

Publisher

Royal Society of Chemistry

DOI

10.1039/c0an00744g

Link to Publisher's Edition

http://dx.doi.org/10.1039/c0an00744g

ISSN (print)

00032654

ISSN (electronic)

13645528

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