一体化碰撞反应（iCRC）-电感耦合等离子体质谱（ICP-MS）法测定地质样品中痕量稀土元素

Determination of Trace Rare Earth Elements in Geological Samples by Integrated Collision Reaction(iCRC)-Inductively Coupled Plasma Mass Spectrometry

钡以及轻稀土元素氧化物对中、重稀土元素的干扰一直是质谱测试中存在的问题。建立了石墨粉垫底碳酸钠-硼酸混合熔剂熔融前处理样品,以103Rh为内标校正,一体化碰撞反应-电感耦合等离子体质谱(ICP-MS)法测定地质样品中稀土元素含量的方法。探讨了碳酸钠-硼酸混合熔剂熔融前处理样品注意事项、碰撞模式下碰撞气流量和离子透镜的参数优化、干扰校正实验等问题,采用国家标准物质GBW07403、GBW07405、GBW07427、GBW07429验证,实验结果表明,各元素线性关系良好,相关系数均大于0.999,方法检出限在0.01~0.03 mg/kg,相对误差为0.13%~7.1%,相对标准偏差为0.79%~6.6%,测定结果与标准值相吻合。对实际样品分析,得到平滑的球粒陨石归一化的稀土元素配分曲线,证明测定结果是合理可信的。方法熔剂用量少,过程空白低,对器皿的侵蚀小,直接加热浸取,简化了操作过程,适用于大批量地质样品中稀土元素的测定。

The interference of barium and light rare earth oxides on medium and heavy rare earth elements has always been a problem in mass spectrometry.A method for the determination of rare earth elements(REEs)in geological samples by ICP-MS with 103Rh as internal standard calibration was established.The precautions for sample pretreatment with sodium carbonate-boric acid mixed flux,optimization of collision gas flow rate and parameters of ion lens under collision mode,interference correction test and so on were discussed.National standard substances GBW07403,GBW07405,GBW07427 and GBW07429 were used for verification.The experimental results show that the linear relationship of each element is good,and the correlation coefficient is greater than 0.999.The detection limit of the method is between 0.01—0.03 mg/kg,the relative error is 0.13%—7.1%,and the relative standard deviation is 0.79%—6.6%.The test results are in good agreement with the standard values.A smooth normalized REE partition curve of chondrites was obtained by analyzing actual samples,which proved that the results were reasonable and credible.The method has the advantages of less flux,low blank,less erosion to vessels,direct heating and leaching,simplifying the operation process,and being suitable for the determination of rare earth elements in large quantities of geological samples.