Fluorimetric determination of D- and L-lactate derivatized with 4-(N,N-dimethylaminosulfonyl)-7-piperazino-2,1,3-benzoxadiazole (DBD-PZ) by high-performance liquid chromatography

A highly sensitive method, based on fluorescence derivatization with 4-N,N-dimethylaminosulfonyl-7-piperazino-2,1,3-benzoxadiazole (DBD-PZ), was developed for the determination of D- and L-lactic acid. High-performance liquid chromatographic separation of the lactic acid derivative was achieved using an octadecylsilica column followed by enantiomeric separation on a phenylcarbamoylated β-cyclodextrin chiral column. The separation factor for D,L-lactic acid derivatives was 1.30 using MeOH/H₂O (80/20) as a mobile phase, and the detection limits were approximately 360 and 300 fmol on column for D- and L-lactic acid derivative, respectively. The proposed method was applied to determine D- and L-lactate in a wine and a lactic drink. Both D- and L-lactate could be determined simultaneously, with the precisions ranging from 3.50 to 5.78% for intra-day and 4.28-9.92% for inter-day determinations. The relative recovery was in the range of 91.6-100%.