铅与呋喃甲酰基吡唑啉酮、联吡啶三元配合物吸附波的研究

Adsorptive Wave of Triple Complex of Lead with Furoylpyrazolone and 2,2′-Dipyridine

在pH=3．51的HAc-NaAc介质中,测得1-苯基-3-甲基4-(α-呋喃甲酰基)吡唑啉酮-5(HPMαFP)与2,2′-联吡啶(dipy)合铅三元配合物的灵敏极谱波(-0．73 V(vs．SCE))。铅浓度在0．002～9×10-6 g／mL范围内与峰电流分段呈良好的线性关系,检测下限为2．0×10-9 g／mL。采用多种电化学方法研究了极谱波的性质和电极反应机理。结果证明,-0．73 V处的极谱波为多元配合物吸附波,峰电流由中心离子Pb2+还原产生。根据直线法测得多元配合物组成为n(Pb2+):n(dipy):n(HPMαFP)=1:1:1,表观稳定常数为5．06×106。体系用于粗盐、蔗糖和化妆品中铅测定,标准回收率为99．3％～100．4％。

In a medium of HAc-NaAc（pH =3.51）, a triple complex is formed via Pb（ Ⅱ ） reacting with 1-pheny1-3-methyl-4- （ a-furoyl ） pyrazolone-5 （ HPMotFP ） and 2,2＇-dipyridine （ dipy ）, and there appears a sensitive polarographic wave at - 0. 73 V （ vs. SCE ） for the triple complex. The peak current exhibits linear relation with the concentration of Pb（ Ⅱ ） from 2 × 10^-9 g/mL to 9 × 10^ -6 g/mL. The detection limit is 2 × 10^-9 g/mL. By using different electrochemical methods, the properties of the polarographic wave and the mechanism of electrode reaction were studied. The results indicate that the polarographic wave at -0. 73 V is an adsorptive wave of the complex：. The peak current is produced by the reduction of the Pb （ Ⅱ） ion . The molar ratio of Pb （ Ⅱ ） with dipy to HPMctFP in the complex is 1：1：1 ; and the conditional formation constant of the complex is 5.06 × 10^6. The method was used to determine lead in thick salt, cane sugar and comestic samples. The recovery is 99. 3% - 100. 4% .