方波阳极溶出伏安法测定大米中的痕量镉

将大米用粉碎机粉碎成米粉，用混合酸浸泡（V（浓硝酸）：V（浓硫酸）=3：2）12h，在通风橱中缓慢加热，滴加混合酸及双氧水消解。以银基汞膜电极为工作电极，铂电极为对极，饱和甘汞电极为参比电极，利用方波阳极溶出伏安法测大米中的痕量镉。在pH=3．0的0．2mol／LNHtCl底液中，峰电流与镉离子的质量浓度在0．01-0．12μg／mL内，峰电流与p（镉）呈良好的线性关系，线性回归方程为Ip497．59c＋15．324，相关系数为0．9941，检出限为4．6074×10-3μg／mL。相对标准偏差为4．12％-5．56％。加标回收卒为90．26％-98．16％．

The Application of Square Wave Anodic Stripping Voltammetry to Measure the Trace Mount of Cadmium in Rice

Rice were grounded into rice powder by muller and soaked in mixed acid solution （concentrated nitric acid： concentrated sulphuric acid=3 ： 2） for 12 hours. Then, the mixture was heated slowly in a hood, and mixed acid solution and aqueous hydrogen peroxide solution were added for the digestion. In order to test the trace amount cadmium in rice with square wave stripping voltammetry method, a three-- electrode system are used with the silver-- based mercury film electrode as working electrode, platinum electrode as counter electrode, and saturated calomel electrode as reference electrode. The results show that a good linear relationship can be obtained in pH = 3. 0 NH4CI（0. 2 tool/L）substrate solution, within the concentration of cadmium 0. 0l - 0. 12μg/mL; the regression equation was Ip = 497. 59c q- 15. 324 with the correlation coefficient of 0. 994 1, the detection limit of 4. 607 4×10-3μg/mL, the relative standard deviation of 4.12%-5.56%, and the recovery rate of 90.26%-98.16%.