土壤和海洋沉积物中16种稀土元素电感耦合等离子体-质谱测定的酸消解体系选择与消除钪元素背景干扰研究

Selection of mix-acids digestion system and elimination of background interference on scandium applied in determination of 16 rare earth elements in soil and ocean sediments by ICP-MS

目的筛选适合于土壤和海洋沉积物中镧(La)、铈(Ce)、镨(Pr)、钕(Nd)、钐(Sm)、铕(Eu)、钆(Gd)、铽(Tb)、镝(Dy)、钬(Ho)、铒(Er)、铥(Tm)、镱(Yb)、镥(Lu)、钇(Y)、钪(Sc)16种稀土元素含量测定的混合酸消解体系以及钪(Sc)背景干扰消除技术。方法采用微波消解技术,选取硝酸+氢氟酸(+硼酸)、王水+氢氟酸(+硼酸)、硝酸+双氧水+氢氟酸(+硼酸)三种混酸体系消解土壤和海洋沉积物有证参考物质,定容后采用ICP-MS直接测定16种稀土元素含量,与标示值比较计算回收率;调节仪器QP Bias与Oct P Bias的差值,消除^(45)Sc的背景干扰。结果王水+氢氟酸、硝酸+双氧水+氢氟酸适用于土壤样本消解,王水+氢氟酸适用于海洋沉积物的消解,改变QP Bias与Oct P Bias的差值为4 V,可以消除45Sc的背景干扰。结论采用微波消解技术+(4 ml王水+0.5 ml氢氟酸)混合酸体系结合ICP-MS技术,可以满足土壤和海洋沉积物类环境样本中16种稀土元素测定要求。

Objective To develop a method for the selection of mix-acids digestion system and elimination of background interference on Sc suitable for determination of 16 rare earth elements in soils and ocean sediments including La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu,Y and Sc. Methods The soil and ocean sediment reference materials were digested by microwave with HNO3＋HF（＋H3BO3）,aqua regia ＋HF（＋H3BO3） and HNO3＋H2O2＋HF（＋H3BO3） respectively,and 16 rare earth elements in digested sample solutions were determined by ICP-MS. The recoveries were calculated to value the effect of three mix-acids optimizing the difference between QP Bias and Oct P Bias to eliminate the background reference induced by45 Sc.Results Aqua regia＋HF and HNO3＋H2O2＋HF were suitable for digestion of soil and aqua regia ＋HF was suitable for digestion of ocean sediments. The 4 V difference between QP bias and Oct P bias could eliminate the background reference induced by45 Sc. Conclusion It is suitable for the determination of 16 rare earth elements in soil and ocean sediments that digestion by4 ml aqua regia＋0.5 ml HF with microwave.