RPIC/ICP-MS测定水中的Cr(Ⅲ)和Cr(Ⅵ)

Simultaneous Determination of Chromium Speciation in Water Using RPIC/ICP-MS

建立了反相离子对色谱-电感耦合等离子体-质谱(RPIC/ICP-MS)联用技术测定水中痕量三价铬Cr(Ⅲ)和六价铬Cr(Ⅵ)的分析方法。通过对流动相的组成、浓度、pH值等色谱条件的实验,确定当流动相组成为0.25mmol.L-1乙二胺四乙酸二钠和2mmol.L-1四丁基氢氧化铵,5%(V/V)甲醇,pH=7.0时,成功分离了Cr(Ⅲ)和Cr(Ⅵ)离子。ICP-MS测定时选用碰撞反应接口技术(CRI)消除40Ar12C+与35Cl16OH+对52Cr+的质谱干扰,Cr(Ⅲ)和Cr(Ⅵ)的检出限分别为0.50、0.34μg.L-1,RSD<10%(n=5)。应用于湖北黄冈、黄石、襄阳等地企业废水中Cr(Ⅲ)和Cr(Ⅵ)含量的测定,加标回收率为86.1%—100.1%。与分光光度法比对,实验证明本方法能克服用分光光度法测定水中六价铬由样品本身带来的干扰。

A method was developed to determination chromium speciation simultaneously in water using reversed-phase ion-pair chromatography with inductively coupled plasma mass spectrometry（RPIC/ICP-MS）.The Cr（Ⅲ） and Cr（Ⅵ） were separated well on C18 column with the mobile phase of 0.25mmol/L ethylene diamine tetraacetic acid disodium salt-2mmol/L tetrabutylammonium hydroxide-5%（V/V）methanol（pH7.0）.The collision response interface was applied to eliminate the mass interferences of 40Ar12C＋ and 35Cl16O1H＋ in the analysis of 52Cr＋.The detection limit of Cr（Ⅲ） and Cr（Ⅵ） are 0.50、0.34 μg·L-1.The recoveries of Cr（Ⅲ） and Cr（Ⅵ） ranged from 86.1%—100.1% with the relative standard deviations（RSDs） less than 10%（n=5）.Cr（Ⅲ） and Cr（Ⅵ） in waste water samples which collected from Huanggang,Huangshi and Xiangyang were analyzed by this method with satisfied recovery of standard addition,this method avoid the interference which caused by sample matrix in spectrophotometry.