锡(Ⅳ)-3,4-二羟基苯甲酸-钒(Ⅳ)体系极谱吸附催化波的研究

Studies on the Polarographic Adsorptive Catalytic Wave of Tin()3,4Dihydroxybenzoic Acid(DHBA)Vanadium() System

在含有３．６×１０－３ｍｏｌ／Ｌ的ＶＯＳＯ４、６．０×１０－５ｍｏｌ／Ｌ的３，４－二羟基苯甲酸（ＤＨＢＡ）、０．１ｍｏｌ／Ｌ的甲酸盐缓冲溶液（ｐＨ３．３）体系中，Ｓｎ（Ⅳ）－ＤＨＢＡ络合物产生一灵敏的吸附平行催化波，峰电位在－０．５２Ｖ（ｖｓ．ＳＣＥ）。二次导数波高与锡浓度在３．４×１０－１０～５．１×１０－７ｍｏｌ／Ｌ范围内呈良好线性关系。检出限达浓度２×１０－１０ｍｏｌ／Ｌ。研究了催化波的性质和电极反应机理。方法已应用于罐头食品中微量锡的测定。

n a 0.1mol/L formate buffer solution(pH3.3) containing 3.610-3mol/L VOSO4 and 6.010-5mol/L 3,4dihydroxybenzoic acid(DHBA),a sensitive polarographic adsorptive catalytic wave of tin()DHBA complex has been obtained by using singlesweep polarography .The peak potential appears at -0.52V (vs.SCE).The secondorder derivative peak height is proportional to the concentration of Sn() over the range from 3.410-10 to 5.110-7mol/L.The limit of detection for Sn() is as low as 210-10mol/L.The properties of the catalytic wave and the mechanism of the electrode reaction have been studied.The method has been successfully applied to the determination of Sn() in canned foods with satisfactory results.