Use of 3-(p-carboxybenzoyl)quinoline-2-carboxaldehyde to label amino acids for high-sensitivity fluorescence detection in capillary electrophoresis
✍ Scribed by Edgar A. Arriaga; Yanni Zhang; Norman J. Dovichi
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 737 KB
- Volume
- 299
- Category
- Article
- ISSN
- 0003-2670
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✦ Synopsis
Detection
of amino acids by laser-induced fluorescence capillary electrophoresis can be achieved by using a fluorogenic reagent, 3-(p-carboxybenzoyl) quinoline-2carboxaldehyde (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 488nm argon ion laser line we obtain a limit of detection of 9.0 zeptomoles (1 zeptomol= 10V21 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 lo-' 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.