Simultaneous determination of cysteine sulfinic acid and hypotaurine in rat tissues by column-switching high-performance liquid chromatography with electrochemical detection.

Cysteine sulfinic acid (CSA) and hypotaurine (HT) were determined by electrochemical detection with a glassy carbon electrode at 0.95 V vs. Ag/AgCl. The separation of CSA and HT was accomplished by coupled-column liquid chromatography, consisting of an anion-exchange column and a cation-exchange column. For the determination of CSA and HT in rat tissues, a column-switching system was introduced to remove interferences from late-eluting endogenous substances. The limits of determination were 0.05 microM for both sulfinic acids. The average precisions (C.V.) over the concentration range of 0.05 to 5 microM were 4.3% for CSA and 4.2% for HT.