Use of 3-(p-carboxybenzoyl)quinoline-2-carboxaldehyde to label amino acids for high-sensitivity fluorescence detection in capillary electrophoresis

Edgar Arriaga, Yanni Zhang, Norman J. Dovichi

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Detection of amino acids by laser-induced fluorescence capillary electrophoresis can be achieved by using a fluorogenic reagent, 3-(p-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQ). This reagent does not fluoresce unless it has reacted with a primary amine to form an isoindole derivative. Using a sheath flow cuvette as a post-column detector and excitation by the 488-nm argon ion laser line we obtain a limit of detection of 9.0 zeptomoles (1 zeptomol = 10-21 mol) for the CBQ-arginine derivative, which is 150 times better than previously reported. We also investigate and optimize the derivatization reaction by successfully labeling arginine concentrations as low as 10 -7 M. CBQ-arginine derivatives from lower concentrations of this amino acid cannot be detected due to secondary reactions of CBQ and cyanide, which generate background peaks that swamp the CBQ-amino acid peak.

Original languageEnglish (US)
Pages (from-to)319-326
Number of pages8
JournalAnalytica Chimica Acta
Volume299
Issue number3
DOIs
StatePublished - Jan 10 1995
Externally publishedYes

Keywords

  • Amino acids
  • Electrophoresis
  • Fluorimetry
  • Labeling
  • Lasers

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