1,3,5,7-Tetramethyl-8-aminozide-difluoroboradiaza-s-indacene as a new fluorescent labeling reagent for the determination of aliphatic aldehydes in serum with high performance liquid chromatography

A BODIPY-based fluorescent derivatization reagent with a hydrazine moiety, 1,3,5,7-tetramethyl-8-aminozide-difluoroboradiaza-s-indacene (BODIPY-aminozide), has been designed for aldehyde labeling. An increased fluorescence quantum yield was observed from 0.38 to 0.94 in acetonitrile when it reacted with aldehydes. Twelve aliphatic aldehydes from formaldehyde to lauraldehyde were used to evaluate the analytical potential of this reagent by high performance liquid chromatography (HPLC) on C18 column with fluorescence detection. The derivatization reaction of BODIPY-aminozide with aldehydes proceeded at 60 °C for 30 min to form stable corresponding BODIPY hydrazone derivatives in the presence of phosphoric acid as a catalyst. The maximum excitation (495 nm) and emission (505 nm) wavelengths were almost the same for all the aldehyde derivatives. A baseline separation of all the 12 aliphatic aldehydes (except formaldehyde and acetaldehyde) is achieved in 20 min with acetonitrile–tetrahydrofuran (THF)–water as mobile phase. The detection limits were obtained in the range from 0.43 to 0.69 nM (signal-to-noise = 3), which are better than or comparable with those obtained by the existing methods based on aldehyde labeling. This reagent has been applied to the precolumn derivatization followed with HPLC determination of trace aliphatic aldehydes in human serum samples without complex pretreatment or enrichment method.