A CYANINE FLUOROPHORE WITH A HYDRAZIDE FUNCTIONALITY AS LABELING REAGENT FOR ALDEHYDES IN LIQUID-CHROMATOGRAPHY

A new hydrazide derivative of a cyanine dye is synthesized for the che mical derivatization of aldehydes. With this red absorbing fluorophore it is possible to apply visible diode laser induced fluorescence (DIO -LIF) detection in conventional-size liquid chromatography (LC). The d ye is based on CY5.3a-IA, a sulfonated dicarbocyanine with a iodoaceta mido reactive group. The detection limit of n-octylaldehyde is 7 x 10( -8) M, limited by the reactivity of the label. Mixtures comprised of s trongly resembling aldehydes were derivatized with the label and analy zed by LC-DIO-LIF. The potential applicability in biological problems is shown by the derivatization of 4-hydroxy-2-nonenal (HNE).