6,7-DIMETHOXY-1-METHYL-2-OXO-1,2-DIHYDROQUINOXALIN-3-YLPROPIONOHYDRAZIDE AS A FLUORESCENCE DERIVATIZATION REAGENT FOR ALDEHYDES IN HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

6,7-Dimethoxy-1-methyl-2-oxo-1,2-dihydroquinoxalin-3-ylpropionohydrazide has been developed as a highly sensitive and selective fluorescence derivatization reagent for aliphatic and aromatic aldehydes. The reaction conditions were optimized with cyclohexanecarbaldehyde, 2-naphthaldehyde and heptanal. The reagent reacted with the aldehydes in the presence of trichloroacetic acid at 60-degrees-C to produce the corresponding fluorescent derivatives, which were separated on a reversed-phase column, L-column ODS, by isocratic elution with 70% v/v aqueous methanol as eluent. The derivatives were detected spectrofluorimetrically at 442 nm with excitation at 362 nm. The detection limits (signal-to-noise ratio = 3) for the aldehydes are 13-18 fmol for an injection volume of 10 mul.