低硼富含有机质的河/雨水正热电离硼同位素的测定

Positive Thermal Ionization Mass Spectrometric Analysis of Boron Isotope on River/Rain Water with Low Content and Rich Organic Matter

对低硼富含有机质的河/雨水样品硼的分离方法及硼同位素组成的测定进行了研究。采用硼特效树脂富集河/雨水样品,结合微升华技术去除有机质;采用正热离子质谱法进行硼同位素组成的测定。全流程回收率在97.50%~101.17%之间,测试数据和多接受电感耦合等离子体质谱比较接近,测试精度小于0.05‰。经本方法处理后的样品能满足同位素质谱测定的需要,样品用量少,测试精密度高,准确性好。

A method for separation and isotopic determination of boron with low content and rich organic matter in the river/rain water samples was developed.Samples were concentrated by ion exchange Amberlite IRA-743 resin.The concentrated solution was subsequently micro-sublimated for 12 h to eliminate the organic matters.Then the boron isotope ratio was determined by measuring positive Cs2BO＋2 thermal ions.The average recovery was between 97.5% and 101.2%.The results that were determined by positive thermal ionization mass spectrometry were closed to those by MC-ICP-MS.The precision of isotopic measurement for boron in river/rain water was better than 0.05‰.The results demonstrated that this method was extremely effective for elimination organic matter interference during boron isotopic analysis with low sample size,high precision and accuracy.