Determination of secondary amino drugs as their metal dithiocarbamate complexes by reversed-phase high-performance liquid chromatography with electrochemical detection.

To assay various secondary amino drugs (sympatomimetic, beta-blocking, antiarrhythmic agents), they were converted to metal (copper or nickel) dithiocarbamate complexes by means of a pre-column derivatization method. The electrochemical properties of the complexes were studied. They were chromatographed on a reversed-phase column (LiChrosorb RP-18) with mixtures of acetate buffer (pH 5.8) and organic solvents (methanol, acetonitrile, ethanol or dichloromethane) as mobile phases. The complexes were detected by amperometry (applied potential of +0.7 V vs. SCE) or by UV spectrophotometry. The procedure has great sensitivity (10(-12) mole for each injected compound) and good selectivity for the more substituted amino drugs.