毛细管微萃取技术联用ICP-MS分析水样中铬的形态

Capillary Microextraction for Speciation Analysis of Cr Prior to Their Determination by ICP-MS

文章以聚(N-(4-乙烯基)-苄基亚氨基二乙酸-二乙烯基苯-N,N’-亚甲基双丙酰胺)(VBIDA-DVB-Bis)作为毛细管整体柱材料,联用ICP-MS测定水样中的三价铬和六价铬。整体柱在一定条件下可选择性吸附样品溶液中三价铬,进而测得三价铬的量。加入一定量的FeSO4可将六价铬还原为三价铬,进而测得总铬的量。六价铬的测定值由总铬测定值减去三价铬测定值计算而得。在0.01~5.00μg/L的浓度范围内,整体柱对三价铬的吸附量信号值与样品浓度呈线性关系(R2=0.9989),该方法对三价铬的检出限LOD为0.017μg/L,日间和日内RSD分别为3.1%和2.6%。对于环境水样中铬的形态分析,三价铬和六价铬加标回收率分别为93.9%±2.7%和93.4%±2.8%,表明该方法适用于环境水样中铬元素的形态分析。

Poly(N-(4-vinyl)-benzylidene diacetic acid-divinylbenzene-N-methylene dipropionamide)(VBIDA-DVB-Bis)was adopted as monolithic capillary microextraction material for the extraction of Cr(III)and Cr(VI)in water samples followed by ICP-MS detection.Under certain conditions,the monolithic column can selectively adsorb Cr(III)to obtain the amount of Cr(III)species.The Cr(VI)can be reduced to Cr(III)by FeSO4 to obtain the total amount of chromium.Then,the Cr(VI)species was calculated by subtracting the amount of Cr(III)species from the total chromium.The adsorption signal value of Cr(III)was linear with the sample concentration(R2=0.9989)in the range of 0.01~5.00μg/L.The detection limit of the method was 0.017μg/L,and the inter-day and intra-day RSD were 3.1%and 2.6%,respectively.For the speciation analysis of chromium in environmental water samples,the recoveries of Cr(III)and Cr(VI)were 93.9%±2.7%and 93.4%±2.8%,respectively,which proved that this method was suitable for the speciation analysis of Cr in environmental water samples.