相敏交流吸附溶出伏安法测定痕量锡  

Determination of Trace Tin by Phase-sensitive Alternating Current Adsorptive Stripping Voltammetry

作　　者：李益恒[1] 朱志伟[1] 

机构地区：[1]湘潭大学化学系,湘潭411105

出　　处：《分析化学》1995年第9期1069-1072,共4页Chinese Journal of Analytical Chemistry

摘　　要：本文研究了锡(Ⅳ)-3,4-二羟基苯甲酸络合物的相敏交流吸附溶出行为.在pH 3.6的甲酸盐缓冲溶液中,该络合物经两步双电子还原在相敏交流伏安图上于—0.33 V和—0.49 V(vs.Ag-AgCl)产生两个吸附还原波,第一个波更灵敏,峰电流与锡(Ⅳ)浓度在1.7×10^(-9)～2.5×10^(-7)mol/L范围内呈线性关系,检测限达4×10^(-10)mol/L(富集30s).测得络合物组成为1:1.方法已应用于罐头食品中锡的测定.结果满意.A sensitive method is described for the determination of trace tin, based on the phase-sensitive a. c. adsorptive stripping of tin( Ⅳ ) complex with 3,4-dihydroxybenzoic acid (DHBA) at a hanging mercury drop electrode. Optimal experimental conditions include the use of 0. 05 mol/L formate buffer solution(pH 3. 6) with 1. 5×10-5 mol/L DHBA, an accumulation potential of -0. 15 V(vs. Ag-AgCl), an a. c. frequency of 30 Hz, an amplitude of 30 mV and a scan rate of 2 mV/s. The adsorbed Sn( Ⅳ )-DHBA complex exhibits two ca-thodic peaks, at -0. 33 and -0. 49 V, corresponding to the reduction of Sn( Ⅳ )-DHBA to Sn( I )-DHBA and Sn( I )-DHBA to Sn(Hg), respectively. The peak current at -0. 33 V is linearly proportional to the concentration of tin(Ⅳ) over the range from 1. 7×10-9 to 2. 5× 10-7 mol/L and the detection limit is 4×10-10 mol/L(30 s accumulation). No serious interferences were found. The method has been applied to the determination of tin in canned food with satisfactory results.

关 键 词：锡 二羟基苯甲酸 伏安法 食品分析 

分 类 号：O614.432[理学—无机化学] O657.14[理学—化学]