摘要
在0.10 mol/L甲酸盐缓冲溶液(pH3.0)中,锡-茜素络合剂络合物在单扫示波极谱仪上产生一灵敏的络合吸附波,峰电位在-0.60 V(VS.SCE),二次导数波高与锡浓度在4.2×10^(-9)～6.7×10^(-6)mol/L范围内呈线性关系。研究了极谱波的性质和电极反应机理。方法已成功地应用于罐头食品中锡的测定。
In 0.10mol/L formate buffer solution containing 3.0×10^(-5) mol/L alizarin complexone aad 0.1% ascorbic acid, at pH 3.0, asensitive adsorptive complex wave of tin-alizarin complexone was obtain-ed at -0.60V (VS.SCE) by using simgle sweep polarography. The changeof peak height with the concentration of tin is linear in the range of 4.2×10^(-9) to 6.7×10^(-6)mol/L. The method has been applied to determine totrace tin in food with satisfactory results. The electrode processes maybe presented as follows:1. In bulk solutionSn (Ⅳ) + H_3L^-(?)=-[Sn(Ⅳ)·HL]^+ +2H_-^+2. The complex diffuses to electrode surface[Sn[Ⅳ)·HL]_-^(?)[Sn(Ⅳ)·HL]^+ads.3. At E_(p1)=-0.3Ⅳ, tin(Ⅳ) in the complexi is reduced[Sn (Ⅳ)·HL]_-^+eds.+2e = [Sn(Ⅱ)·HL]^-ads.4. At E_P2=-0.35Ⅴ, ligand in the complex is reduced[Sn(Ⅱ)·HL]^-ads. + 2e+ 2H^+ = [Sn(Ⅱ)·HL']^-ads.5. At E_P3=-0.60Ⅴ, tin(Ⅱ) in the complex is reduced[Sn(Ⅱ) ·HL']^-ads. + 2e + 2H_-^+=Sn(Hg) + (H_L')^-ads.where H_3L^-and H_3L'- are the anthraquinone and dihydroanthraquinone of alizarin compclexone respectively.
出处
《湘潭大学自然科学学报》
CAS
CSCD
1991年第1期80-84,共5页
Natural Science Journal of Xiangtan University
关键词
锡
测定
茜素络合剂
示波极谱
tin
alizarin complexone
single sweep polarography
