电位溶出法测定污泥中的痕量铅和镉

Determination of Pb2+ and Cd2+ in Sludge Samples by Potential Stripping Analysis

关键词:  污泥  铅  镉  电位溶出法

Key words:  sludge  plumbum  cadmium  potential stripping analysis

摘要:

在HAc-NaAc缓冲溶液(pH值5.0)中,铅、镉离子分别于-0.47V(vs.SCE)和-0.67V(vs.SCE)可得到灵敏的电位溶出峰,峰高与溶液中铅、镉离子的浓度(0~20μg/L)呈线性关系,线性回归方程分别为dt/dE=2.4823C_Pb²⁺-0.0937(r=0.9992);dt/dE=1.872C_Cd²⁺+0.1299(r=0.9990)。检出限分别为0.08μg/L和0.06μg/L。该方法用于测定实际污泥样品中痕量铅和镉的含量,结果与石墨炉原子吸收法测定的结果基本吻合。利用电位溶出法测定污泥中痕量重金属,具有灵敏度高,准确度好,仪器筒单,操作简便等特点。

Abstract:

A sensitive method for the determination of trace amount of lead and cadmium in sludge by potential stripping analysis (PSA) using mercury film electrodes is proposed. In HAc NaAc buffer solutions,Pb²⁺ and Cd²⁺ exhibit stripping peaks[dt/dE-f(E)] at -0.47V and -0.67V (vs SCE) respectively. There are linearship between the peak heights and the concentration of Pb²⁺ and Cd²⁺. The regress equations of linearity that dt/dE=2.4823 C_Pb²⁺-0.0937(r=0.9992);dt/dE=1.872 C_Cd²⁺+ 0.1299(r=0.9990) are obtained. The detect limits of Pb²⁺ and Cd²⁺ are 0.08 and 0.06 μg/L respectively. The method is sensitive,selective,rapid and simple that applied to determination of trace lead and cadmium in sludge samples with satisfactory results.