摘要
在ｐＨ为６．７的０．０２ｍｏｌ／Ｌ柠檬酸盐缓冲溶液中，铅－茜素紫配合物在单扫示波极谱仪上分别于－０．５７Ｖ和－０．７１Ｖ（ｖＳ．ＳＣＥ）产生两个极谱还原波，第二个波的二次导数峰电流与铅（Ⅱ）浓度在２．０×１０－８～４．０×１０－８ｍｏｌ／Ｌ范围内呈线性关系，检测极限为１×１０－８ｍｏｌ／Ｌ．详细研究了茜素紫及其铅（Ⅱ）配合物的电极反应机理．用拟定的方法测定了大米和蔬菜中的铅，结果满意．
In 0. 02 mol/L citrate buffer solution at pH 6. 7, alizarin violet exhibits a reduction peak (p3) at-0. 87V(vs. SCE) on single-sweep polarogram. After adding lead (Ⅱ), two new peaks appear at-0.57V(P1) and -0. 71V(p2). Experimental results showed that the peak p1 is a kinetic wave preceded by a chemical reaction, the peak p2 corresponds the reduction of lead (Ⅱ) bonded in the lead (Ⅱ)-alizarin violet complex adsorbed on the surface of the mercury electrode and the peak p3 can be assigned to the irreversible two-electron reduction of ring carbonyl group in molecule of adsorbed alizarin violet. The composition of the complex was found to be 1: 1. The second derivative peak current of p2 is linearly related to the concentration of lead (Ⅱ) in the range from 2. 0×10-8 to 4. 0×10-6mol/L. The detection limit is 1×10-8mol/L. The method has been applied to the determination of lead in biological samples with satisfactory results.
出处
《湘潭大学自然科学学报》
CAS
CSCD
1994年第3期45-49,共5页
Natural Science Journal of Xiangtan University
关键词
铅
茜素紫
单扫描极谱
铅络合物
lead
alizarin violet
single-sweep polarography
