Determination of thiopentone sodium in aqueous and biological media by cathodic stripping voltammetry

摘要

A simple and more sensitive cathodic stripping voltammetric methodis described for the determination of short-anaesthetic drug thiopentone-sodium (TPS).The method is based generally on the formation of a slightly soluble mercury salt of TPS with Hg onto HMDE surface.The reduction current of the formed salt was measured by bothlinear sweep (LSCSV)and differential pulse cathodic stripping voltammetry(DPCSV).Different variables were studied and optimized.Four-fold enhancement in the current is observedin the presence of trace Mg ion. As low as 1x10~(-8)moll~(-1)(2.60 ppb) and 2x10~(-9)moll~(-1)(0.53ppb)with accumulation time 240 and 300s,in the absence and in the presence of Mg(II),respectively,have been determined using both techniques,with the relative standard deviation up to 3.5%(n=4).The interferences of some metal ions,ascorbic acid and amino acids were studied.The determination of the drug in pure pharmaceutical dosage form,urine,and human serum samples have been successfully carried out.The results were compared favorably with the official methods.