硝酸钾-硫氰酸铵-水体系萃取浮选铜间接测定甲巯咪唑

Indirect determination of thiamazole by extraction flotation copper(Ⅱ) with potassium nitrate-ammonium thiocyanate-water system

建立了KNO3-NH4SCN-水体系萃取浮选铜间接测定甲巯咪唑的新方法。研究表明：在SCN^-存在下，控制溶液pH4．0～6．0，Cu（Ⅱ）可被甲巯咪唑分子中的巯基还原生成的Cu（Ⅰ）与SCN^-形成CuSCN白色乳状沉淀，加入KNO3可使该沉淀浮选至水相表面，通过测定溶液中剩余Cu（Ⅱ）的量，从而间接测定甲巯咪唑的含量。CuSCN的浮选率（E％）与甲巯咪唑的质量浓度呈良好的线性关系。当Cu（Ⅱ）加入量为50ug时，测得线性范围为0．25～3．00ug／mL（相关系数为0．9996）。检出限为0．097ug／mL。该法可用于片剂、血清、尿样中甲巯咪唑的测定。

A novel method for indirect determination of thiamazole by extraction flotation of copper （ Ⅱ ） with potassium nitrate-ammonium thiocyanate-water system was developed. The experiment indicated that at pH 4.0 to 6.0, in the presence of SCN^-, Cu （ Ⅱ ） could be reduced to Cu （ I ） by thiamazole and the resulting Cu （ Ⅰ ） can react with SCN- to form white emulsion precipitate CuSCN. In the presence of KNO3, this precipitate was ascended and floated on the surface of water. The amount of thiamazole can be determined by measuring the flotation yield of Cu （ Ⅱ ）. When the amount of added Cu（ Ⅱ ） is 50/lg, the linear range is maintained in the range 0.25 - 3.00 ug/mL with a correlation coefficient of 0. 9996. The detection limit is 0. 097 ug/mL. This proposed method had been successfully applied to the determination of thiamazole in tablets, urine and human serum with satisfactory results.