6,7-Dimethoxy-1-methyl-2-oxo-1,2-dihydroquinoxalin-3-ylpropiono-hydrazide as a fluorescence derivatization reagent for aldehydes in high-performance liquid chromatography

Abstract

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 °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 µl.