国产电感耦合等离子体质谱仪测定地球化学样品中稀土和铀钍元素的含量

Determination of rare earth elements,U and Th in geochemical samples by inductively coupled plasma mass spectrometry

用国产电感耦合等离子体质谱仪（ICP-MS）建立了测量地球化学样品中稀土和铀钍元素含量（La、ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、U、Th）的方法。样品在高温密闭环境下用氢氟酸-硝酸-高氯酸三酸混合消解。溶液通过在线三通进入雾化器，选择元素Re作为内标测量样品中各元素的含量，选择质谱干扰较少的元素谱线进行测量。采用多点标准获得的标准曲线的线性相关系数大于0．999，通过测量空白溶液得出大部分元素的仪器的检出限在0．001-0．01ng·mL^-1左右。实验测量得到仪器的氧化物产率为2．8％，双电荷产率为2．1％，短期稳定性（20min）优于3％，长期稳定性（2h）优于5％。实验测试了多种国家标准物质，测量值与参考值吻合。

A method for the determination of 16 elements （La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm,Yb,Lu,Th,U） by inductively coupled plasma mass spectrometry with instrument made in China has been developed. Samples were digested with mixed acid of HF-HNO3-HC104 in closed vessel. Rhenium was used as an on-line internal standard by a three-way tube. The effect of spectra interferences were mini- mized by selecting proper mass value. The linear correlation coefficient of calibration equation was better than 0. 999, the detection limits of the instrument for those elements were vary from 0. 001 to 0.01 ng·mL^-1. Molecular oxides ratio of the instrument was 2. 8%, doubly charged ions ratio was 2. 1%, short term stability of 20 minute was better than 3%, and long term stability of 2 hours was about 5%. Six kinds of national standard reference materials were used to test the method, the analytical results were in agreements with the certified values.