Simple reversed-phase high-performance liquid chromatographic method for 13-cis-retinoic acid in serum

An isocratic reversed-phase high-performance liquid chromatographic method for the analysis of 13-cis-retinoic acid in serum is developed. Sample preparation includes deproteination with acetonitrile-perchloric acid-acetic acid followed by centrifugation. 9-Methylanthracene is used as the internal standard. Chromatographic separation is achieved on a C18 column (Zorbax) using an acetonitrile-aqueous 0.5% acetic acid (85:15, v/v) eluent containing 0.05% (w/v) sodium hexanesulfonate. The limit of detection is 12 ng/ml in serum, using 0.5 ml samples. Quantitative recoveries and excellent intra-day and inter-day precision are reported.