3-(2-Furoyl)quinoline-2-carboxaldehyde (FQCA) is a fluorogenic derivatizing reagent for liquid chromatography suitable for high-sensitivity analysis of amino acids by laser-induced fluorescence with an argon-ion laser. The reagent forms highly fluorescent isoindoles upon reaction with primary amines. It is used for the determination of isoelectronic points (pI values) of proteins with laser-induced fluorescence detection (c-IEF-LIF). C-IEF-LIF technique can routinely detect 10-11 M of FQCA-labeled protein, compared with 10-7 M by traditional slab gel IEF and silver staining.