测定水体中镉的维多利亚艳蓝BO-碘分光光度法

Determination of Trace Cadmium in River Water by Victoria Pure Blue BO-Iodide Spectrophotometry

目的建立一种测定河水中痕量镉的新方法。方法用巯基棉富集分离河水中痕量镉,在含4×10^(-3)％乳化剂OP的H3PO4-NaH2PO4溶液中,维多利亚艳蓝BO与[CdI4]2-反应生成离子缔合物,溶液颜色由黄色变为艳蓝色,分光光度法测定河水中痕量镉。结果镉富集50倍,离子缔合物表观摩尔吸光系数ε=2.79×10~5L/(mol·em),线性范围2-100μg/L,回收率96.2％-98.6％,相对标准偏差2.5％。结论方法准确、灵敏,可应用于水体中痕量镉的测定。

Objective To establish a new method for determination of trace cadmium in river water. Methods Cadmium in river water was separated and enriched with sulfhydryl cotton, in the presence of 4×10~3 % emulsifier OP and H3PO4-NaH2PO4 water solution, Victoria Pure Blue BO reacted with [CdI4]2- forming an ionic-associated complex and the color of the solution changed from yellow to pure blue, and the content of trace cadmium in river water was determined by spectrophotometry. Results When cadmium was enriched fifty times, the apparent molar absorptivity of the associated complex was ε=2.79×10_5 L/(mol·cm). Beer's law was obeyed in the range 2-100 μg/L. The recovery rate and RSD of the method was 96.2%-98.6% and 2.5% respectively. Conclusion The method was accurate and sensitive,and was suitable for determination of trace cadmium in river water.