双硫腙-乳化剂OP光度法测定锌的研究

摘要

研究在表面活性剂存在下，双硫腙分光光度法测定微量锌的方法.在pH4.7的乙酸-乙酸钠缓冲溶液中加入掩蔽剂，在非离子型表面活性剂乳化剂OP存在下，锌离子与双硫腙反应形成红色络合物，其络合比为2∶1，最大吸收波长位于540 nm处.锌离子的质量浓度在0~1.2μg·mL-1与吸光度成较好的线性关系，符合朗伯比尔定律，其线性回归方程为y=0.1185x+0.0019，相关系数r=0.9982，表观摩尔吸光系数为ε=7.80×104 L·mol-1·cm-1.此方法重复性好，灵敏度高，选择性好，可用于测定样品中微量锌，其加标回收率为96.8%~102.7%.%The determination of zinc with the color reaction of dithizone and emulsifier OP was investigated in the presence of surfactant. By adding a masking agent to acetic acid sodium acetate buffer solution in the pH4.7, the results show that dithizone and zinc can form a red complex at 540 nm in the presence of nonionic surfactant emulsifier OP and the molar ration of zinc to dithizone in the complex which is estimated to be 2∶1. The linear range of the calibration curve is 0~1.2 μg·mL-1 with a correlation coefficient of 0.998 2 and the lin-ear regression equation for Y=0.118 5+0.001 9xy = 0.118 5 x + 0.001 9, its amolar absorptivity is 7.80 ×104 L·mol-1·cm-1.This proposed method can be used to determine the content of zinc in samples with good repeata-bility, high sensitivity and good selectivity. The adding standard recovery is between 96.8%to 102.7%.