化学修饰石墨探针预富集－石墨炉原子吸收法测定Cr（Ⅵ）和Cr（Ⅲ）

Determination of Cr ( Ⅵ ) and Cr(Ⅲ)by Chemi-cally Modified Graphite Probe Preconcentration withGraphite Furnace Atolnic Absorption

本文将化学修饰石墨探针选择性预分离富集和石墨炉探针原子化测定的高灵敏度结合起来，建立了用ＴＯＰＯ修饰的石墨探针络合富集Ｃｒ（Ⅵ）、Ｎａｆｉｏｎ修饰的石墨探针交换富集Ｃｒ（Ⅲ）的双修饰石墨探针顺序预分离富集、石墨炉探针原子化法测定水体中Ｃｒ（Ⅵ）和Ｃｒ（Ⅲ）的方法。Ｃｒ（Ⅲ）的检出限为１．０３ｎｇ／ｍＬ，线性范围为０～５１ｎｇ／ｍＬ。Ｃｒ（Ⅵ）的检出限为０．３７ｎｇ／ｍＬ，线性范围为０～８１ｎｇ／ｍＬ。用Ｃｒ（Ⅲ）与Ｃｒ（Ⅵ）合成样品进行回收实验，回收率对Ｃｒ（Ⅲ）与Ｃｒ（Ⅵ）分别为９５％～９８％与９８％～１０２％，利用所建立的方法测定了清华运河水样和实验室自来水样，获得了满意的结果。

n this pape,by combining TOPO and Nafiontwo chcmically modified graphite probes,sequentialpreseparation and concentraton with graphite furnaceatomic absorption,a method of direct determinationfor Cr(Ⅵ)and Cr(Ⅲ) in water was proposed. Thelimit of detection and the linear range of calibrationcurve are 0.37ng/mL and 0～80ng/mL for Cr(Ⅵ)and 1.03ng/mL and 0～51ng/mL for Cr(Ⅲ)respec-tively. Using synthetic sample of Cr(Ⅲ)and Cr(Ⅵ),the coverv is 98%～102%for Cr(Ⅵ ) and 95%～98%for Cr(Ⅲ).This mothod was applied to the determi-nation of Cr(Ⅵ)and Cr(Ⅲ)in running water in thelaboratory and in water in Qinghua canal. Satisfactoryresults were obtained.