浊点萃取-分光光度法测定铝合金中痕量镍的研究

Study on the determination of trace nickel in aluminum alloy by cloud point extraction-spectrophotometry

在pH9.5的Na2B4O7-NaOH缓冲溶液中和非离子表面活性剂Triton X-114存在下,1-(4-硝基苯基)-3-(5,6-二甲基-1,2,4三氮唑)-三氮烯(NPDMTT)与Ni 2+生成的络合物被萃取到表面活性剂Triton X-114中,经离心分相后,以475nm和540nm为测定波长,采用分光光度法对表面活性剂富集相中镍进行测定。实验结果表明,表面活性剂富集相用乙醇(1∶2)稀释后,测得络合物的表观摩尔吸光系数为7.293×105L.mol-1.cm-1,校准曲线的线性范围为0～0.14μg/mL,相关系数为0.999 3。建立的方法用于铝合金样品中镍的测定,测定结果与参考值相符,6次测定结果的相对标准偏差小于3%。

In Na2B4O7-NaOH buffer solution at pH 9.5 in the presence of nonionic surfactant Triton X-114,the complex formed by 1-（4-nitrophenyl）-3-（5,6-dimethyl-1,2,4-triazole）-triazene（NPDMTT） with Ni^2＋ could be extracted into surfactant Triton X-114.After phase separation by centrifuging,the content of nickel in surfactant enrichment phase was determined by spectrophotometry using 475 nm and 540 nm as measuring wavelength.The experimental results showed that,after diluting the surfactant enrichment phase with ethanol（1∶2）,the measured apparent molar absorptivity of complex was 7.293×10^5 L·mol^-1·cm^-1.The linear range of calibration curve was 0-0.14 μg/mL with correlation coefficient of 0.999 3.The proposed method was applied to the determination of nickel in aluminum alloy samples,and the results were consistent with reference values.The relative standard deviation（RSD,n=6） was less than 3 %.