β修正──丁基罗丹明B－OP新光度法测定工业废水中砷含量

Beta-modified Spectrophotometry to Improve the Determination of Arsenic in Waste Water with Butyl Rhodamine B

在酸性溶液中，砷（Ａｓ￣（５＋））与丁基罗丹明Ｂ（ＢＲＢ）反应，显色液由红色变紫色，非离子表面活性剂ＯＰ能提高分析灵敏度并增大ＢＲＢ及其与砷络合产物溶解性。本文研究β修正光度法测定工业废水中痕量砷，它能消除过量ＢＲＢ的干扰提高分析灵敏度、精密度和准确度。结果表明砷浓度０～０．４０ｍｇ／Ｌ时，修正吸光度有良好线性关系，检出限０．００４ｍｇ／Ｌ，加标回收率９３．０％～１１１％，相对标准偏差ＲＳＤ≤６．５％。该方法适合于化工废水、城市污水及各种环境水质分析。

The reaction of arsenic(V)with butyl rhodamioe B(BRB)was developed in acidic solution.The nonionicsurfactant,OP was found to increase the analysis sensitivity and dissolubility of BRB and its As complex. Beta-modified spectrophotometry has been applied for the determination of trace amounts of arsenic in environ-mental water with the increased sensitivity because of the elimination of the excess BRB from its As colouredsolution. The accuracy and precision were still both improved. Results showed that Beer's law was obeved inthe concentration range 0～0.40 mg/L As and the recovery of arsenic is from 93.0%to 111% with RSD ofless than 6.5%. The detection limit of As is equal to 0.004 mg/L which is low enough to satisfy the analysisof waste water.