紫外-可见分光光度法间接测定硫普罗宁的含量

Indirect Determination of Tiopronin by UV-Vis Spectrophotometry

将硫普罗宁片剂样品研磨,用水溶解、稀释,配制成待测样品溶液。于10 mL比色管中依次加入2.00 mL Pd^(2+)标准溶液、4.00 mL待测样品溶液和1.00 mL乙酸-乙酸钠缓冲溶液(pH 5.0),用水定容、摇匀、静置5~10 min。以硫普罗宁标准溶液为参比,于345 nm处测定体系的吸光度。结果显示:在弱酸性环境中,硫普罗宁与Pd^(2+)形成了物质的量比为2∶1的络合物;硫普罗宁的质量浓度在0.20~60.00 mg·L^(-1)内与其对应的吸光度呈线性关系,检出限(3s/k)为0.0035 mg·L^(-1);对实际样品进行加标回收试验,回收率为98.0%~103%,测定值的相对标准偏差(n=5)为0.83%~3.5%。方法用于实际样品分析,测定值与其标示量基本一致。

The sample of tiopronin tablets was ground,dissolved and diluted with water to prepare the sample solution for test.2.00 mL of Pd^(2+) standard solution,4.00 mL of the sample solution for test and 1.00 mL of acetic acid-sodium acetate buffer(pH 5.0)were successively added into a 10 mL colorimetric tube,and the mixture was made its volume with water,shaken well and settled for 5-10 min.The tiopronin standard solution was used as reference,and the absorbance of the system was determined at 345 nm.It was shown that tiopronin and Pd^(2+) formed a complex at molar ratio of 2∶1 in a weak acidic environment.Linear relationship between mass concentration of tiopronin and its absorbance was kept in the range of 0.20-60.00 mg·L^(-1),with detection limit(3s/k)of 0.0035 mg·L^(-1).Recovery test was made on the actual samples,giving results of in the range of 98.0%-103%,and RSDs(n=5)of the determined values were ranged from 0.83% to 3.5%.This method was used for analysis the actual samples,and the measured values were basically consistent with the labeled amounts.