封闭压力酸溶-电感耦合等离子体质谱法同时测定电气石中29种元素

摘要

电气石是一种含硼的铝硅酸盐矿物,是重要的非金属矿产资源和成岩成矿作用的灵敏示踪剂,因类质同象置换普遍使其组成成分多变,主量元素为Si、B、A1、Fe和Mg,微量元素有稀土元素、Cu、Pb、Zn、Sn、Ag和Sr等.电气石的化学性质非常稳定,不能被一般的酸或碱完全溶解,本文采用硝酸-氢氟酸封闭压力溶矿,50％王水封闭压力复溶进行样品前处理,建立了电感耦合等离子体质谱法测定电气石中稀有轻金属、重金属、放射性金属、稀土元素等29种元素的分析方法.方法检出限为0.003 ～ 0.4 μg/g,精密度(RSD,n=12)为0.9％ ～9.2％;国家标准物质的测定值与标准值基本相符,各元素的加标回收率为95％ ～ 105％.本方法解决了电气石样品难分解、复溶时易出现氢氧化铝微细残渣的问题,样品试液中B、Al、Fe等主要共存离子的干扰小,各待测元素测定结果准确、可靠.%Tourmaline is a boron-containing aluminosilicate mineral,which is an important non-metallic mineral resource,and an indicator for rock-forming and ore-forming processes.The chemical composition of tourmaline is highly variable due to the isomorphic substitution.The major elements of tourmaline are Si,A1,B,Fe and Mg,whereas the trace elements are rare earth (REE),Cu,Pb,Zn,Sn,Ag and Sr.The stable chemical properties make it difficult to complete digestion by acid or alkaline reagents.Samples were digested by HNO3-HF in a sealed and pressurized device.50％ aqua regia was used to repeat dissolution.Twenty nine trace elements in tourmaline including precious light metals,heavy metals,radioactive metals and rare earth elements were determined by Inductively Coupled Plasma-Mass Spectrometry.The detection limits (n =12) ranged from 0.003 to 0.4 μg/g and the relative standard deviations (RSD,n =12) ranged from 0.9％ to 9.17％.The proposed method was applied to the determination of certified reference materials and the results were consistent with the certified values.The recoveries of elements ranged from 90％ to 110％.This method solves the problem for difficult dissolution of the tourmaline sample and the fine residue of aluminum hydroxide in the redissolution process.The coexisted ions B,Al and Fe in sample solutions show only slight interference,and the measurement results are accurate and reliable.