乳化剂OP存在下胶束增溶分光光度法测定水中镉

目的：用胶束增溶分光光度法测定水中镉的含量，并比较了乳化剂OP(聚乙二醇辛基苯基醚)和吐温-20(聚氧乙烯山梨醇酐单月桂酸酯)的胶束增溶作用。方法：分别以体积分数为10％OP和体积分数为10％吐温-20为增溶剂，以PAN(1-(2-吡啶偶氮)-2-萘酚)为显色剂，在555nm波长处测定水中镉络合物的吸光度。结果：相同条件下，同浓度的镉络合物用OP的吸光度值是吐温-20的1．6倍，用OP作乳化剂平均回收率为96．5％，平行样品的相对平均偏差为2．57％，标准曲线线性良好，回归系数r=0．999 9，ε=4．6×104L·mol-1·cm-1。结论：乳化剂OP的增溶作用优于吐温-20，此法测定水中痕量镉较好。

Determination of Cadmium in water by the colloidal sheaf-increasing dis-solution in the presence of surfactant OP

Aim: To determine the content of cadmium in water by the spectrophotometry of colloidal sheaf-increasing dissolu-tion and compare the effects of colloidal sheaf-increasing dissolution of 10% (V/V) OP with that of 10% (V/V) TWEEN-20 asbeing emulsifying agents. Methods:Using 10% (V/V) OP and 10% (V/V) TWEEN-20 as increasing dissoluble agents, andPAN as developing dye,the absorption of the complex compound of cadmium was measured at 555 nm. The content of the tracecadmium in water sample was determined. Results: Under the same experiment conditions and with the same cadmium content, theabsorption of the complex compound in 10% (V/V) OP was 1.6 times as that in 10% TWEEN-20.The average recovery ratiowas 96.5 % in the presence of surfactant OP. The relative average deviation of parallel sample was 2.57 %. The standard curve hadbetter line and the regressive coefficient of this curve was r = 0.999 9, ε = 4.6 × 104 L·mol-1· cm-1. Conclusion: Increasing dis-solution of emulsifying agent OP was better than that of TWEEN-20. This is an ideal method of determination of content of tracecadmium in water.