微波消解-电感耦合等离子体发射光谱法测定固体沥青中微量金属元素

Determination of Trace Metal Elements in Solid Bitumen with Microwave Digestion by Inductively Coupled Plasma-Atomic Emission Spectrometry

原油、沥青中的微量元素信息已被应用于油气勘探和油气地球化学研究,然而沥青的分析方法较少,而且前处理过程繁琐。本文将微波消解法应用于沥青样品的消解,电感耦合等离子体发射光谱法测定固体沥青中Al、Ca、Fe、K、Mg、Mn、Na、Ti、Ba、Mo、Ni、Sr、V等13种微量金属元素。在高压密闭条件下,微波消解系统消解固体沥青样品的速度快,并确定了样品量和消解条件等影响因素。不同组合消解试剂优化实验研究表明,浓硝酸-氢氟酸作为消解试剂效果最好;通过实验验证在样品处理过程中没有发生损失和污染情况,精密度(RSD,n=8)小于5%,回收率在92.2%～101.0%之间,元素的方法检出限可达0.05μg/g。本方法为沥青类样品中微量元素分析测定提供了新的参考方法。

Trace element information in crude oil and bitumen has been applied to oil and gas exploration and geochemical study, but the analysis methods of bitumen are limited and the pretreatment process is tedious. To overcome this, microwave digestion was used to digest the solid bitumen sample and a method was developed for the determination of the 13 trace elements Al, Ca, Fe, K, Mg, Mn, Na, Ti, Ba, Mo, Ni, Sr and V by Inductively Coupled Plasma-Atomic Emission Spectrometry （ICP-AES）. The bitumen sample can be digested quickly in closed vessels by microwave at high temperature and pressure. The optimization experiment of the different digestion reagents systems showed that HNO3-HF digestion system was the best to decompose the solid bitumen. Experimental conditions and sampling weight are discussed. The results show that the method can be used to digest the bitumen sample without loss of volatile elements and contamination in the process of digestion. The recoveries of the method were in the range of 92.2% - 101.0% with the precision of less than 5.0% RSD （ n = 8 ） , and the detection limit was up to 0.05μg/g. This method can provide a new reference method for the determination of trace metal elements in solid bitumen.