丁二酮肟复合铋膜修饰电极测定痕量铅

Determination of Trace Pb( Ⅱ) Using Platinum Electrode Modified with Bismuth Film and Dimethyl Glyoxime

目的：通过探讨缓冲溶液、 pH、丁二酮肟和镀铋液浓度、富集时间、富集电位对方波溶出伏安法测铅的影响，建立了一种快速测定水样痕量铅的新方法。方法采用丁二酮肟复合同位镀铋膜修饰铂电极，用方波溶出伏安法对水样中痕量铅进行测定。结果在优化的实验条件下，2.0＆#215;10-8～1.0＆#215;10-5 mol/L范围内Pb2＋峰电流与浓度呈良好的线性关系（ r≥0.9963），富集时间为240 s时， Pb2＋的检出限为2＆#215;10-9 mol/L。结论该法操作简便、灵敏度高、检测限低，且样品经简单消解后即可直接用于测定，无需复杂的富集分离过程。与石墨炉原子吸收法比较，结果一致性较好，效果满意。

Objective A series of experimental conditions , such as the buffer solution , pH, concentration of dimethyl glyoxime and bismuth , the deposition time and potential , were optimized , when the trace lead was determined by square wave voltammetry （ SWSV ） . The method was developed for the quick determination of Pb 2＋in water .Methods Bismuth film modified platinum electrode was prepared by an ex-situ plating above a layer of dimethyl glyoxime for determination of trace lead in the water sample by SWSV.Results Under the optimization experiment conditions , the peak currents changed linearly with the concentrations of Pb 2＋in the range of 2.0 ＆#215;10 -8 ~1.0 ＆#215;10 -5 mol/L （ r≥0.996 3 ） .When its preconcentration time is 240 s, the detection limit can reach 2 ＆#215;10 -9 mol/L.Conclusions This method is simple , high sensitivity , low detection limit and can detect directly after simple digestion without enrichment and separation steps .It has been applied to determine trace lead in the waters samples with satisfactory results that was similar to those of atomic absorption spectrophotometry .