A novel pre-column derivatization reaction for the determination of dithiocarbamates in plasma by high-performance liquid chromatography

A new, fully automated pre-column derivatization reaction was developed for the quantitative determination of dithiocarbamates in plasma samples. For complexation, an aliquot of the sample was mixed with an aliquot of a 5 mM Co(II) solution on the autosampler tray. Optimum conditions for the reaction were achieved at a tray temperature of 20 °C and a reaction time of 11 min. Liquid chromatography (LC) separation was performed on a C18 ODS column using a binary gradient consisting of phosphate buffer and methanol. The colored complex of dithiocarbamate and Co(III) was quantified by UV detection at 330 nm. The assay was applied for the determination of pyrrolidine dithiocarbamate, a potent antiviral compound for the inhibition of human rhinoviruses and influenza viruses, in plasma samples. Limits of quantification were 1.4–2.9 (mu)g ml^-1.