银丝汞膜电极伏安法测定药品中头孢氨苄

VOLTAMMTRY DETERMINATION OF CEPHALEXIN IN PHARMACEUTICAL PRODUCTS WITH SILVER MERCURY MEMBERANE ELECTRODE

本文以银丝汞膜电极为工作电极，在０．１０ｍｏｌ／ＬＮａＯＨ溶液中经１００℃水浴加热２０ｍｉｎ后，用线性扫描伏安仪制作ＣＥｘ的阴极还原曲线，其峰电位－０．７５Ｖ（ＶＳＡｇ／ＡｇＣｌ），浓度在２．０×１０－７～２．１０×１０－６ｍｏｌＬ－１；２．０×１０－６～２．０×１０－５ｍｏｌＬ－１范围内，峰高与浓度呈线性关系，其线性回归方程ｉ（格）＝１．２８６×１０６ｃ－０．１５０４（ｒ＝０．９９５８，ｃ：２．０×１０－５～２．０×１０－６ｍｏｌ／Ｌ）；ｉ（格）＝１．２３×１０６＋０．７８７０（ｒ：０．９９７３，ｃ＝２．０×１０－６～２．０×１０－７ｍｏｌＬ－１）．方法应用于胶囊中ＣＥｘ的含量测定并与药典法相比，结果基本一致．此外利用循环伏安等方法对其降解产物电化学行为进行初探，该体系属于准可逆吸附体系．

A new method has been established for determination of cephalexin on Silver mercury membrane electrode, This method is based on the electro chemical behaviour of Its degradation product after hydrolysis in sodium hydroxide for 20 minutes at 100℃. In a supporting electrolyte containing 0.1mol/L NaOH and E i=-0.40v, T=60s, v=100mv/s, a sensitive reduction derivative peak of the degradation produet of cephalexin was obtained by liner sweep voltammetry. The peak potential was Ep=-0.75v(Vs Ag/AgCl), The liner relationship between derivative peak height and the concentration of cephalexin held in the rang of 2.0×10 -7 -2.0×10 -6 mol/L(r=0.9973); 2.0×10 -6 -2.0×10 -5 mol/L(R=0.9958), This method was applied to the pharmaceutical analysis. The electrochemical behavious in the system has been studied by means of linear sweep and cyclic voltammetry. The wave was confirmed to be of a quasirersible adsorptive nature.