Study On Determination Of Micro - Trace Copper, Lead, Cadmium And Nickel In Zinc Chloride - Ammonium Chloride Solution By Voltammetry

Zinc chloride and Ammonium solution system is mainly used in industrial electrogalvanized and zinc electrolysis, the content of impurity ions in solution affects the quality of the product directly. Therefore, we have to monitore for these ions. The traditional measurement methods such as titration, spectrophotometry, inductively coupled plasma atomic emission spectrometry (ICP-AES), oscillopolarography method, in terms of the determination of trace levels of ions in solution has been very matured. But these methods accuracy is low on measurement of trace ion. It is difficult to meet the monitoring needs of the actual production of deep purification process, and not easy to achieve rapid detection on line. Therefore, explore ing a rapid and accurate detection analysis method of zinc chloride-ammonium chloride solution marks the amount of impurity element is very important.This paper established ammonia-zinc-ammonium chloride system, determined trace, trace amounts of copper, lead, cadmium and nickel by differential pulse stripping voltammetry. The method uses ammonia masking zinc, dimethylglyoxime complex nickel, and the method can eliminate the interference of a large number of zinc, nickel cadmium, without sample pretreatment. Under the experimental conditions optimized, the peak potential of copper, lead, nickel and cadmium were -0.28 V,-0.47 V,-0.63 V and-1.03 V. Calibration curve in the range of 3.2×10-8～1.6×10-6 mol/L、7.9×10-9～3.2×10-5 mol/L、2.1×10-8～9.8×10-5 mol/L、1.7×10-8～9.5×10-6mol/L, respectively; The detection limit were 1.4×10-8mol/L、3.9×10-9mol/L、1.9×10-9mol/L、7.8×10-9mol/L, respectively; The relative standard deviation were 0.10%～3.7%, and the recovery were 90% to 109%.Under the same system, the determination of copper, lead, cadmium and nickel using differential pulse polarographic peak potential were 0.08 V,-0.28 V,-0.55 V,-1.05 V, respectively; The linear range of the calibration curve 5.3×10-6～1.6×10-4、6.1×10-7～ 2.4×10-4、1.3×10-6～8.0×10-4、5.5×10-6～4.3×10-4mol/L, respectively; The detection limits were 1.8×10-6、1.5×10-7、8.0×10-7mol/L, respectively; The relative standard deviation were 1.2% to 2.7%, and the recovery rate were 84% to 112%.Two methods can be applied to trace copper, lead, cadmium and nickel testing of actual electrolyte and differential pulse stripping voltammetry had good detection limits. Paper uses two methods on the actual sample detection comparison with ICP-AES of the supernatant was neutral plating solution, and the results showed that the three methods were good consistency in the determination of trace copper, lead, cadmium and nickel.