薄膜梯度扩散-分光光度法富集测量水中痕量Cr(VI)

Determination of Cr(VI) in Water by the Diffusive Gradients in Thin-Films Technique Combined with Diphenylcarbazide Spectrophotometry

建立了薄膜梯度扩散（DGT）-二苯碳酰二肼（DPC）分光光度法富集测量水中痕量Cr（Ⅵ）的分析方法.先以聚季铵盐（PQAS）溶液为结合相的DGT技术（PQAS DGT）原位分离富集水中Cr（Ⅵ）,再以DPC分光光度法测定DGT结合相中Cr（Ⅵ）的含量,最后依据DGT方程计算水中Cr（Ⅵ）的浓度.DGT-DPC法测得配制水中Cr（Ⅵ）的回收率为95.1％～101.3％,相对标准偏差为1.60％～3.58％;测得工业废水中Cr（Ⅵ）的浓度为18.54 ～ 137.61μg/L,加标回收率为94.3％～101.8％.当采样时间为48h,PQAS DGT对水中Cr（Ⅵ）富集近10倍,可显著降低分析方法的检测限,实现水中痕量Cr（Ⅵ）的定量检测.

Cr（Ⅵ） in water was pre-concentrated by the diffusive gradients in thin-films （DGT） technique with poly（quaternary ammonium salt） （PQAS） as binding phase （PQAS DGT） and measured by diphenylcarbazide （DPC） spectrophotometry. The recoveries of Cr（VI） in the synthetic solutions measred by the DGT-DPC method were 95.1% - 101.3% with RSD of 1.60% - 3.58%. The concentration of Cr （Ⅵ） in industrial wastewaters measured by the DGT-DPC method was 18.54 - 137.61μg/L with recoveries of 94.3% - 101.8%. The enrichment factor of Cr（VI） pre-concentrated by PQAS DGT was 10 （deployment time 48h）. Therefore, the DGT-DPC method can be used to measure trace Cr （VI） in water.