Determination of thiram using polarographic catalytic wave in presence of Cu(II)

The polarographic catalytic wave of the thiram and Cu2+ in tartaric acid, potassium sodium tartrate and persulfate systerm was used for the determination of tniram. In 0.1 mol/L C4H6O6-C4H4O6KNa (pH = 5.5) + 3.0 x 10(-3) mol/L K2S2O8 + 4.0 x 10(-6) mol/L Cu2+ base solution, the peak potential of the polarographic catalytic wave was set at -0.8 V (vs. SCE), and the second derivative peak current of the catalytic wave was linearly proportional to the thiram concentration in the range of 1.0 x 10(-8) - 1.0 x 10(-6) mol/L (r = 0.9994). The detection limit was 2.0 x 10(-9) mol/L. The relative standard deviations was 1.2% (n = 10). The reductive peak current of thriam was 12 nA, and the corresponding catalytic current was 1.5 x 10(3) nA. Thus the sensitivity of the catalytic wave of thiram was 125 times higher than that of the corresponding reduction wave. The recovery was between 83.8% and 91.4%. The method is sensitive, simple and rapid.