摘要
用线性扫描示波极谱法研究了钴(Ⅱ)-硫辛酸体系的伏安行为,发现在pH=8.5的NH3-NH4Cl缓冲溶液中,钴(Ⅱ)在硫辛酸的存在下,于-0.55 V(vs,SCE)处左右产生一尖锐、灵敏的二次导数极谱波,峰电流与钴(Ⅱ)浓度在3.0×10-8～3.0×10-6 mo1/L范围内呈线性关系,检出限为1.0×10-8 mo1/L.研究了该波的性质及电极反应机理,证明该波为络合吸附波,钴(Ⅱ)与络合剂的组成比为1∶1,电子转移数n=2,不可逆吸附的转移系数α=0.59.该方法用于VB\-12中痕量钴的测定,结果满意.
In NH3-NH4Cl buffer solution, at pH 8.5, a sensitive second derivative polarographic wave of Co （ Ⅱ ）- lipoic acid complex appears at -0.55V（vs. SCE）. The peak current is proportional to cobalt concentra- tion in the range of 3 × 10^-8 ～ 3 × 10^-6 mol·L^-1 the detection limit is 1 × 10^- 8 mol·L^-1. Several electrochemical methods have been used to study the properties of the wave and the mechanism of electrode. It is proved that the wave is a complex adsorptive one. The molar ratio of Co（ Ⅱ ） to lipoic acid is 1 ： 1. The number of electrons transferred （n） is 2 and the transfer coefficient （α） is 0.59 . This method has been successfully applied to the determination of trace total cobalt in vitamin B12.
出处
《喀什师范学院学报》
2005年第6期43-45,共3页
Journal of Kashgar Teachers College
关键词
钴
硫辛酸
络合吸附波
Cobalt
Lipoic acid
Complex adsorptive wave
