The determination of thiomalate in physiological fluids by high-performance liquid chromatography and electrochemical detection.

Methods are described for the determination of free thiomalate in the plasma and urine of patients receiving the anti-rheumatic drug sodium aurothiomalate. Thiomalate is separated by reversed-phase chromatography and detected using a gold electrochemical cell. Plasma analyses require maximal sensitivity while urine estimations require selectivity rather than sensitivity: different phosphate buffer-methanol eluents and electrode potentials are used. On-column sensitivity for thiomalate is 40 fmol injected.