摘要
采用双硫腙-TBP萃取光度法快速测定电镀废水中微量镉.在磷酸盐的中性缓冲溶液中,双硫腙-TBP显绿色,与镉离子生成橙红色配合物.镀镉废水中的干扰离子用钛铁试剂-酒石酸钾钠-碘化钾联合掩蔽.镉-双硫腙配合物萃取至有机相直接进行光度法测定.试验结果表明,在500 nm波长处,表观摩尔吸光系数为6.0×104L·mol-1·cm-1,Sandell灵敏度为0.0019μg·cm-2;5 mL有机萃取相中镉含量在0～8.0 μg/5 mL符合比耳定律.应用电镀废水样品中微量镉的直接萃取测定,分析结果的相对偏差小于2.8%,回收率为99.5%.
It was found that in a phosphate buffer solution of pH 7, the dithizonate complex of cadmium（ Ⅱ ） can be quantitatively extracted into tributyl phosphate （TBP） which acts both as the solvent for dissolution of dithizone（DTZ） and for extraction of the complex. The absorbance of cadmium dithizonate complex was measured at its absorption maxima of 500 nm, where the apparent molar abosrptivity was found to be 6. 0 ×10^4 L ·mol^-1· cm^-1 and the sandell sensitivity to be 0. 001 9μg · cm^-2. Beer＇s law was kept for below 8. 0μg of Cd（ Ⅱ ） in 5 mL of TBP solution. In applying the above mentioned method to the analysis of electroplating waste water, the interference of co-existing ions was studied and a mixed solution containing tiron, sodium potassium tartrate and potassium iodide was chosen as masking agent to eliminate the interferences. In the direct photometric determination of CA（ Ⅱ ） in waste water samples, the relative deviation obtained were less than 2. 8%, and recoveries in the range of 99.5%.
出处
《理化检验（化学分册）》
CAS
CSCD
北大核心
2005年第11期843-844,850,共3页
Physical Testing and Chemical Analysis(Part B:Chemical Analysis)
基金
上海市教育委员会重点培育学科基金项目Y04013
关键词
萃取光度法
双硫腙
镉
电镀废水
Photometry
Solvent extraction
Dithizone
Cadmium（ Ⅱ ）
Electroplating waste water
