摘要
将青霉素G钠盐在pH 4.6条件下水解成青霉氨基酸;以银电极为阳极,电解产生滴定剂Ag+,以Ag+滴定青霉氨基酸,采用电位法确定库仑滴定终点,由电解定律计算青霉素G钠盐含量。此法取代了汞量法,消除了汞污染,相对误差为0.184%,RSD(n=11)为0.030%。
Constant current-coulornetry was applied to the determination of penicillin G（socilum salt） in arug powder. The sample was preliminarily hydrolyzed in alkaline solution and in acetate buffered solution of pH 4.6 in succession to convert penicillin G into penicillic amino acid. Based on the quantitative reaction of -SH group in the molecule of penicillic amino acid with silver（ Ⅰ ） to form a precipitate with the formula （CH3）2-C-（SAg）-CH（NH2 ）- COOH, the content of penicillin G （sodium salt） was determined coulometrically by titration with silver ion electrogenerated at the silver anode. The quantity of penicillin G was calculated by the Faraday＇s law. Small amounts of penicillic amino acid was usually found in the unhydrolyzed penicillin G sample due to degradation, a separate, unhydrolyzed sample should be taken to determined this blank value, which after converted into amounts of penicillin G, was substracted from the＇ total value of penicillin G. The substitution of this coulometric method for the mercurimetric method makes it possible to avoid the use of mecury salts and is favorable to enviromental protection. A check for the accuracy and precision of the present method was made by analyzing a reference sample （labelled value of penicillin G content （w） is 98. 04%）, relative error of 0. 184%, and RSD （n= 11） of 0. 030% were obtained, which were both better than those obtained by the mercurimetric method.
出处
《理化检验（化学分册）》
CAS
CSCD
北大核心
2005年第12期914-916,共3页
Physical Testing and Chemical Analysis(Part B:Chemical Analysis)
基金
江苏省高校自然科学研究指导性计划项目(04KJD150182)
关键词
恒电流库仑分析法
银离子
青霉素G钠盐
青霉氨基酸
Constant eurrent-eoulometric titration
Electro-generated silver ion
Benzyl penicillin （penicillin G） sodium salt
Penicillic amino acid
