一种电位溶出法测定重金属离子的信号处理方法  

Signal processing method for the determination of heavy metals ions by potentiometric stripping analysis

作　　者：杜明 卢阳 廖玉枝 曾小明 司士辉[1] DU Ming;LU Yang;LIAO Yu-zhi;ZENG Xiao-ming;SI Shi-hui(School of Chemistry and Chemical Engineering,Central South University,Changsha 410083;Hunan Testing Institute of Product and Commodity Supervision,Changsha 410007)

机构地区：[1]中南大学化学化工学院,长沙410083 [2]湖南省产商品质量监督检验研究院,长沙410007

出　　处：《分析试验室》2019年第10期1157-1162,共6页Chinese Journal of Analysis Laboratory

基　　金：国家自然科学基金项目(21727810);湖南省质量技术监督管理局科研项目(201801)资助

摘　　要：基于化学计量学方法将微分电位溶出(DPSA)采样信号dt/dE对t1/2求导得到Y值,将Y对E作图得到Y-E电位溶出曲线,推导出Y-E电位溶出法近似定量分析关系式和理论响应曲线方程。通过Pb^2+,Cd^2+,Sn^4+,As^3+,Ag^+电位溶出分析实验对Y-E电位溶出曲线方程,峰高与金属离子浓度、沉积时间以及氧化剂浓度的关系进行验证,实验结果证明了理论曲线方程和近似定量分析关系式的正确性。与DPSA信号相比,经该信号处理方法得到的信号值增大约2.41/τ1/2倍,半峰宽由65.5 mV/n改善到29.0 mV/n,线性相关性优于DPSA信号,且峰值更易准确测量。将该方法应用于检测大米中的镉含量,并与DPSA所得结果进行比较,回收率和精密度均优于DPSA,可应用于食品中重金属含量的测定。Based on the stoicheiometry method,the Y value was obtained by deriving the signal value of dt/dE in the differential potentiometric stripping analysis(DPSA)to t1/2.Then Y was plotted against E to obtain the Y-E potentiometric stripping analysis curve,deriving the approximate quantitative analysis relationship and theoretical response curve equation of Y-E potentiometric stripping analysis.The Y-E potentiometric stripping curve equation and the relationship between peak height and metal ion concentration,deposition time,and oxidant concentration were investigated by potentiometric stripping determination of Pb^2+,Cd^2+,Sn^4+,As^3+and Ag^+ions.The experimental results proved the correctness of theoretical curve equation and approximate quantitative analysis.Compared with the DPSA signal,the signal value increased by approximately 2.41/τ1/2 times and the half width was improved from 65.5 mV/n to 29.0 mV/n by the present signal processing method,the linear correlation was better than DPSA signal and the peak was easier to measure accurately.The method was applied to the detection of cadmium content in rice,and compared with the results obtained by DPSA,the recovery and precision were better than those of DPSA,which can be applied to determine the content of heavy metal in food.

关 键 词：重金属 微分电位溶出法 化学计量学 信号处理 

分 类 号：O657.1[理学—分析化学]