固相萃取—ICP-MS分析西藏咸水湖泊中的微量元素

Determination of trace elements in saline lakes in Tibet by ICP-MS after the solid-phase extraction

本研究建立了一种以NOBIAS PA1螯合树脂为富集手段,结合电感耦合等离子体质谱(ICP-MS)测试富含有机碳的咸水湖泊中Mn、Fe、Co、Ni、Cu和Zn的分析方法.该方法首先使用UV/H2O2法对湖泊水体进行消解,去除有机络合作用对Co和Cu的干扰;然后对咸水中的微量元素进行预富集,并使用醋酸铵去除树脂上吸附的盐类;最后使用HNO3洗脱样品并用ICP-MS进行测试.结果表明,在pH值6.35±0.30的情况下,不同微量元素流程空白值为0.49~6.43ng/kg;检出限为0.17~4.55ng/kg;样品的回收率为99%~102%.该方法用于西藏雅根错、色林错、昂仁金错的测试结果显示,该方法加标(内标元素In)回收率>99%;样品(n=3)的相对标准偏差<5%.本方法适用于内陆湖泊尤其是富含有机质的咸水湖泊(包括盐湖)微量元素分析.

A novel method was developed using a NOBIAS PA1 chelating resin with an inductively coupled plasma mass spectrometry(ICP-MS)measurement for Mn,Fe,Co,Ni,Cu,and Zn in organic-rich saline lakes.First,H2O2 was added to the samples which were subsequently irradiated with a digester containing three low-pressure ultraviolet lamps.This UV/H2O2 method could destroy the organic ligands of Co and Cu in water to reduce their interference.Then,the trace metals were pre-concentrated through a chelating resin column.The column was rinsed with an NH4AC solution to remove the loaded salts.Finaly,the trace metals were eluted with HNO3 solution and analyzed by ICP-MS.Results showed that the procedural blanks and detection limits of the trace elements were 0.49~6.43 ng/kg and 0.17~4.55 ng/kg,respectively,at a pH of 6.35±0.30.All trace metals were quantitative,and their recovery rates were 99%~102%.The results from the application of this method to Yagen Co Lake,Selin Co Lake,and Angren Jin Co Lake in Tibet showed that the recovery rates of Indium internal standard were>99%,and the relative standard deviations of the samples(n=3)were less than 5%.These findings suggests the method developed in this paper could be used to analyze trace metals in inland lakes,especially in organic-rich saline lakes(including salt lakes).