【摘要】 提出了以Cu（Ⅱ）为探针,分光光度法测定药物中半胱氨酸含量的方法。研究表明:在pH 4.0的乙酸盐缓冲溶液中,半胱氨酸中的巯基（—SH）能使Cu（Ⅱ）还原成Cu（Ⅰ）,生成的Cu（Ⅰ）与SCN^-反应生成CuSCN沉淀,所得Cu（Ⅱ）的量为定量生成CuSCN沉淀后留存的过量Cu（Ⅱ）的量,将此Cu（Ⅱ）的测定值间接换算成试样中半胱氨酸的含量。溶液的吸光度和半胱氨酸的质量浓度在0.20～9.0 mg·L^-1之间呈线性关系,表观摩尔吸光率为6.05×10⁴ L·mol^-1·cm^-1。方法用于模拟样品中半胱氨酸含量的测定,回收率在96.0%～103%之间,测定值的相对标准偏差（n=6）在0.67%～1.4%之间。更多还原

【Abstract】 A method of spectrophotometry for the determination of cysteine in medicines using Cu（Ⅱ） as probe was proposed.It was found that in a acetate buffer solution of pH 4.0,Cu（Ⅱ） was reduced to Cu（Ⅰ） by mercapto group（—SH） of cysteine,and Cu（Ⅰ） produced was precipitated with SCN as CuSCN.Amount of cysteine was calculated indirectly from the analytical results of Cu（Ⅱ） present in the solution.Linear relationship between values of absorbance of solution and mass concentration of cysteine was kept in the range of 0.20—9.0 mg ? L^-1,and value of apparent molar absorptivity found was 6.05×10⁴’ L ? mol^-1 ? cm^-1.The proposed method was applied to the determination of cysteine in simulative water,giving values of recovery and RSD’s（n = 6） in the ranges of 96.0%—103%and 0.67%—1.4%respectively.更多还原