紫外-可见分光光度法间接测定西咪替丁的含量

Indirect Determination of Cimetidine by UV-Vis Spectrophotometry

建立了紫外-可见分光光度法间接测定西咪替丁含量的方法。在西咪替丁样品溶液中加入Cu2+溶液,用0.1 mol·L^(-1)氢氧化钠溶液和0.1 mol·L^(-1)盐酸溶液调节溶液至pH 7,并用pH 7的乙酸-乙酸钠缓冲液维持溶液酸度,西咪替丁与Cu2+形成稳定的Cu2+-西咪替丁配合物,该配合物在325 nm处产生明显的特征紫外吸收峰,通过测定其吸光度来间接测定西咪替丁的含量。结果显示:西咪替丁的质量浓度在一定范围内与其对应的Cu^(2+)-西咪替丁配合物体系的吸光度呈线性关系,检出限(3s/k)为3.00 mg·L^(-1)。对实际样品进行3个浓度水平的加标回收试验,西咪替丁的回收率为95.3%~102%,测定值的相对标准偏差(n=5)为1.2%~2.9%。

A method for the indirect determination of cimetidine by UV-Vis spectrophotometry was established.Cu2+solution was added to cimetidine sample solution,then the solution was adjusted to pH 7 with 0.1 mol·L^(-1)sodium hydroxide solution and 0.1 mol·L^(-1)hydrochloric acid solution,and kept the acidity with acetic acid-sodium acetate buffer solution(pH 7),and stable Cu2+-cimetidine complex was formed with an obvious characteristic absorption peak at 325 nm.The content of cimetidine was determined indirectly by measuring absorbance of the complex.Linear relationship between mass concentration of cimetidine and the absorbance of Cu2+-cimetidine complex system was kept in a definite range,with detection limit(3s/k)of 3.00 mg·L^(-1).Recovery test was made on the actual samples by standard addition method at 3 concentration levels,giving recovery in the range of 95.3%-102%,and RSDs of the determined values(n=5)were ranged from 1.2%to 2.9%.