不同原油中金属元素的测定及聚类分析

Determination of Trace Metal Elements in Different Crude Oils and Their Cluster Analysis

采用二氯甲烷溶解、分散原油样品,以浓HNO3-H2O2为消解体系,采用微波法对原油进行消解,利用电感耦合等离子体质谱法(ICP-MS)测定原油中的V、Ni、Cu、Fe、Cr、Zn、Pb、Co、Mo、Ag等17种微量金属元素;并以6Li、45Sc、72Ge、89Y、115In、159Tb、209Bi为内标元素,补偿基体效应,选择适当的待测元素同位素克服质谱干扰,优化了实验条件。结果表明,原油中大多微量金属元素的检出限达到ng/L,仅Fe、As、Sb 3种元素的检出限相对较高;各元素线性关系良好,相关系数r不低于0.999 5;方法精密度较高,相对标准偏差(RSD)不大于5.0%,准确度较好,相对误差不高于10%。对不同原油样品以Ni/V与Fe/V值为变量进行聚类分析,结果发现,国内与国外不同地区原油样品具有明显差异性。

An inductively coupled plasma mass spectrometric（ICP-MS） method was developed for the determination of V,Ni,Cu,Fe,Cr,Zn,Pb,Co,Mo,Ag,etc.in different crude oil.The oil sample dispersed firstly in organic solvent（CH2Cl2） and was digestded by microwave using HNO3-H2O2 as oxidant.^6Li,^45Sc,^72Ge,^89Y,^115In,^159Tb and ^209Bi were selected as the internal standard elements.The matrix effect was compensated and the MS interference was corrected by selecting the suitable isotope of the elements.The experimental conditions were optimized.The results showed that,except for Fe,As and Sb,the detection limit of other elements could reached ng/L level.The correlation coefficients were not less than 0.999 5.The RSDs were no more than 5.0%,and the relative error was no more than 10%.The ratios of Ni/V and Fe/V of different crude oils were further analyzed by cluster analysis.The result showed that a big difference exisited in different crude oils from domestic and overseas.