流动注射光度法测定废水中的磷酸盐

Determination of phosphate in wastewaters by flow injection analysis spectrophotometry

在H2SO4介质中,磷酸盐与钼酸铵形成磷钼杂多酸,磷钼杂多酸被还原剂抗坏血酸还原成磷钼蓝,据此建立了流动注射直接测定污废水中磷酸盐的快速方法。在优化的试验条件下,当磷酸盐质量浓度在0.1-1.5 mg/L时,浓度与峰高呈良好的线性关系;检出限为0.05 mg/L;重复测量相对标准偏差为2.2%（0.5 mg/L磷酸盐,n=11）。利用本法测定污水厂排出水中的磷酸盐,回收率在97.0%-102.5%之间。

Phosphate and ammonium molybdate could form phosphorus molybdenum heteropoly acid in a sulphuric acid medium. The phosphorus molybdenum heteropoly acid could be reduced to phosphomolybdate blue by the reducing agent ascorbic acid. Based on the above principle the flow injection direct measurement of phosphate in wastewater was established. Under the optimum conditions,a linear calibration graph is obtained in the range of 0. 1 - 1. 5 mg / L. The detection limit is 0. 05 mg / L with the relative standard deviation of 2. 2%（ 0. 5 mg /L,n = 11） and the spike recoveries are between 97. 0% and 102. 5%. This method has been applied to wastewater determination.