The ATTO-TAG™ CBQCA derivatization reagent (CBQCA; 3-(4carboxybenzoyl)quinoline- 2-carboxaldehyde) reacts specifically with primary amines to form conjugates that can be analyzed by electrophoretic or chromatographic methods. The resulting products of CBQCA are maximally excited at 450 nm or by the 442 nm spectral line of the He-Cd laser and have emission maxima at ∼550 nm. In capillary zone electrophoresis (CZE), the sensitivity of detection of ATTO-TAG™ CBQCA conjugates should be in the attomole range (10-18 moles). The high sensitivity, freedom from background and long-wavelength excitability make these potential reagents for researcher, diagnostic and forensic applications.