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

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.