Electrophoretic determination of thioamides, pyridine and pyrimidine derivatives

We have optimized the conditions for the separation and quantification of a mixture of heteroaromatic thioamides, potential thyreostatics: pyridine-2-thione (I), 5-trifluoromethylpyridine-2-thione (II), pyrimidine-2-thiol (III), 4-trifluoromethylpyrimidine-2-thiol (IV) by capillary zone electrophoresis using a 60 cm × 75 μm capillary (effective length of 50 cm), 15-kV voltage, and borate buffer solution (pH 9.18) as the running electrolyte. The procedure provides the estimation of analyte concentrations in the range from 6.7 × 10 −6 to 1.0 × 10 −4 M with the detection limits (by electrophoretic peak areas) 0.72 (I), 0.47 (II), 0.43 (III), and 0.76 (IV) μg/mL.