地下水样品中硼同位素组成的测定

Determination of boron isotopic composition in groundwater samples

对地下水样品进行硼分离及其同位素组成及TIMS测试。针对地下水硼含量低、有机质含量高的特点,将样品采用C18固相萃取柱去除有机质,建立阴离子交换树脂法分离硼,并与混合离子交换树脂法分离结果进行对比。结果表明:两种分离流程回收率均在95%以上。样品经前处理后能满足同位素热电离质谱的测试要求,几乎不产生明显的同位素分馏,阴离子交换树脂法测量精度小于0.06%,且能够在分离的同时实现富集,更适用于地下水样品。

A method for the separation and isotopic composition determination of boron in the groundwater samples was developed.According to the characteristics of low boron content and high organic matter content in groundwater,C18 column was selected to remove the organic matter.A single ion exchange resin method was established to separate boron,and the separation results were compared with those obtained by double ion exchange resin method.The total process recovery rate of the two separations is above 95%.After pretreatment,the sample can meet the determination conditions of thermal ionization mass spectrometry without isotopic fractionation,the test accuracy of single ion exchange resin method is less than 0.06 and can enrich boron content while separating the organic matter,which is more suitable for determining groundwater samples.