电感耦合等离子体质谱法测定碳酸盐岩中30种痕量元素及干扰校正研究

应用电感耦合等离子体质谱法(ICP-MS)分析碳酸盐岩样品中的痕量元素,其中高钙基体的存在会对元素的分析信号产生明显的抑制或增强作用,从而引起显著的基体干扰。本文研究了硝酸-盐酸-高氯酸-氢氟酸四酸敞开溶样体系下ICP-MS同时测定碳酸盐岩中30种痕量元素的方法。重点分析了质谱干扰包括样品基体本身所带来的谱线干扰、同量异位素干扰和多原子离子干扰,并对钙含量高的碳酸盐岩样品中Ca对Ni的干扰进行了试验,分别采用数学公式或干扰系数等方法对干扰因素进行校正,使分析结果得到了明显改善。标准物质的测定值与标准值基本一致,方法精密度(RSD)除个别元素为10%~15%,大多数元素均小于10%,符合地质样品分析规范要求。

Determination of Thirty Trace Elements in Carbonate Rocks by Inductively Coupled Plasma-Mass Spectrometry and Interference Correction

High calcium content in carbonates will result in obvious inhibition or enhancement of element analysis signals when samples are determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In this study, carbonates were openly dissolved by HNO₃, HCl, HClO₄ and HF, and 30 trace elements were determined by ICP-MS. The mass spectrum interferences due to sample matrix, isobaric effect and polyatomic ions are evaluated. The interference of Ca on Ni for high-Ca samples is also evaluated. By using formula and interference coefficients, the analytical results are obviously improved. Analytical values are in accordance with the standard values, and relative standard deviation (RSD) is less than 10%, except for some elements, which have RSDs of 10%-15%, confirming the requirement of analytical criteria.