利用MC-ICPMS对水样中硼同位素比值的测定  

Determination of boron isotope ratios in aqueous samples by multiple collector ICP-MS

作　　者：吕苑苑[1] 许荣华[1] 赵平[1] 谢烈文[1] 李禾[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球化学》2008年第1期1-8,共8页Geochimica

基　　金：国家重点基础研究发展计划项目(2002CB412606)

摘　　要：采用Amberlite IRA-743硼特效树脂进行水溶液中硼的分离,对洗脱液温度、体积以及树脂动态交换容量等进行了实验。它的动态交换容量为4.2mg/g,在室温条件下,用5mL2%HNO3可定量从树脂柱上洗脱被吸附的硼。采用Neptune型MC-ICPMS进行硼同位素组成的测定,1μg/g浓度的硼标准溶液获得放大的信号强度约为0.7V,硼的化学分离过程有效避免了质量歧视效应。实验结果表明,MC-ICPMS对硼存在严重的记忆效应,通过采用5%HNO3-(1%HNO3+0.1%HF)-H2O-20% NH3H2O-H2O的交替清洗方法,可在约1h内消除硼的记忆效应。在最佳仪器条件下,对含有250ng硼的水样,可以快速测定硼的同位素组成,δ11B测定的绝对偏差为0.4‰～0.5‰(SD)。Boron can be separated from aqueous samples with Amberlite IRA-743 resin. And the tests on the temperature and the volume of elute and the dynamic exchange capacity of the resin are finished. The dynamic exchange capacity of the resin is 4. 2 mg/g. In room temperature 5 mL 2% HNO3 can quantitatively extracted boron fixed on the resin. Boron isotope ratios are measured using Neptune MC-ICPMS. The magnified signal intensity of 1 μg/g B standard solution is 0. 7 V. The separation processes of B can effectively avoid mass bias. The results indicate that there are serious memory effects on boron in MC-ICPMS and these effects can be solved by carrying out an alternate wash process with 5% HNO3-（l% HNO3 ＋0. 1% HF） -H2O-20% NH3H2O-H2O in about 1 h. Under the optimal conditions of the instrument, it is possible to measure boron isotope ratios in the aqueous sample containing 250 ng boron with a precision of ±0.4‰-0.5‰（SO）.

关 键 词：硼同位素 Ambedite IRA-743 MC-ICPMS 水样 

分 类 号：P597[天文地球—地球化学]