石墨消解-等离子体质谱法测定天然橡胶中14种元素的含量

建立了石墨消解-等离子体质谱（ICP-MS）法快速测定天然橡胶中铅、镉、铜、铬等14种无机元素的方法,旨在为天然橡胶中多元素检测标准的制定提供研究基础。通过优化石墨消解法的前处理条件,再应用ICP-MS测定天然橡胶样品中14种元素（Ba、Na、Mg、K、Ca、Cr、Mn、Fe、Ni、Cu、Zn、Cd、Pb、Co ）的含量,采用在线内标校正基体效应和信号漂移,以确保数据准确性。结果表明,该方法具有较低的检出限,检出限范围为0.0014~0.020 mg/kg,方法回收率86%~96%,RSD在0.53%~6.13%,得到的线性关系良好,充分满足实验要求。石墨消解法操作简便,可按照设定程序自动完成消解全过程,消解时间固定,适用于大批量样品的检测分析,同时,设备以及耗材成本较低。与传统干灰化-原子吸收光谱法相比,本检测方法更适用于天然橡胶中14种无机元素含量的测定,具有耗时短、干扰小、检测范围宽、处理效率高等优点,适用于大批量橡胶样品的多元素检测分析。已应用本实验方法,快速测定了我国6个橡胶主产区中的天然橡胶样品。

Determination of 14 Elements in Natural Rubber by Graphite Digestion-inductively Coupled Plasma Mass Spectrometry

To provide a research basis for the formulation of multi-element testing standards in natural rubber, a method for the rapid determination of 14 inorganic elements such as lead, cadmium, copper and chromium in natural rubber by graphite digestion-plasma mass spectrometry (ICP-MS) was established. Different conditions were designed to determine the pretreatment conditions of the graphite digestion method, and then ICP-MS was applied to determine the content of 14 elements (Ba, Na, Mg, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Cd, Pb, Co) in the natural rubber samples, and the matrix effect and signal drift were corrected by the Internal Standard Method to ensure the accuracy of the data. The method had a low limit of detection (LOD) in the range of 0.0014 to 0.020 mg/kg, with a recovery between 86% and 96% and RSDs between 0.53% and 6.13%. The obtained linear relationship was good and fully met the experimental requirements. The graphite digestion method was easy to operate and could be completed automatically according to the set procedure. The digestion time was fixed, which was suitable for the detection and analysis of large quantities of samples. At the same time, it featured low cost in equipment and consumables. Compared with traditional dry ashing atomic absorption spectrometry, the method is a better choice for the determination of the content of 14 inorganic elements in natural rubber, which is characterized by short time consumption, little interference, wide detection range and high processing efficiency and is suitable for multi-element detection and analysis of a large number of rubber samples. This experimental method has been applied to determine natural rubber samples from six major rubber producing areas in China rapidly.