浊点萃取-分光光度法测定水环境中的痕量磷酸盐

Determination of Trace Phosphate in Water Samples by Spectrophotometry with Cloud Point Extraction

建立了分光光度法测定水样中痕量磷酸盐的浊点萃取分离富集新体系。在酸性条件下,以抗坏血酸、钼酸铵作为磷钼蓝比色法测定磷含量的显色剂,酒石酸锑钾作为催化剂,形成稳定的磷钼蓝后,通过80℃水浴加热10m in,磷钼蓝被萃取到T rition X-100表面活性剂相并与水相分离。将表面活性剂富集相用0.5mL乙醇分散稀释,应用紫外-可见分光光度计进行400—1000nm范围内的波长扫描。在最佳条件下,测定的线性范围为0.3—180ng/mL,方法的检出限为0.73ng/mL,相对标准偏差(RSD)为2.8%。该法用于实际水样的富集和测定,结果令人满意。

A novel separation and concentration system for determination of trace phosphate in water samples was established by spectrophotometry with the cloud point extraction（CPE） technique.The method used ammonium molybdate and ascorbic acid as chromogenic agents that was appled to detect the content of phosphorus by colorimetry of phosphomolybdenum blue,and potassium antimonyl tartrate as catalyzer in acidic medium.After formation steadily,the phosphomolybdenum blue was heated for 10 minutes by water bath at 80℃,and then separated from water phase by extraction to the phase containing Trition X-100 surfactant.The surfactant-rich phase was dissolved and diluted by 0.5mL ethanol solution,and scanned from 400nm to 1000nm by ultraviolet-visible spectrophotometer.Under the optimized conditions,linearity was obeyed in the range 0.3—180ng/mL for phosphate.The limit of detection was 0.73ng/mL and relative standard deviation was 2.8%.The method was applied to determination and concentration of orthophosphates in the water samples with satisfactory results.