Abstract: The content of metal elements in crude oil was quantitatively analyzed by inductively coupled plasma optical emission spectrometry ( ICP-OES) ，and the uncertainty analysis method was established．The result shows that the contribution of uncertainty component and sources were evaluated from five aspects，and its relative standard uncertainties were calculated respectively．When the contents of vanadium, nickel, calcium and lead in the sample were 51.68, 11.39, 26.39, and 25.66 μg/g, respectively their corresponding expanded uncertainties were 1.834, 2.491,1.149, and1.119 μg/g. By comparing the contributions of the five uncertainty components, it was concluded that the primary influencing factor was the calibration curve fitting, followed by standard solution preparation and measurement repeatability.Applying this method, vanadium and nickel contents in 73 batches of crude oils imported fromMiddle East were determined, with vanadium ranging from 9.50 to 103.53 μg/g and nickel from 9.33 to 30.52 μg/g. These results enabled statistical classification and construction of a geochemical fingerprinting. This work aims to provide scientific support for origin tracing, quality control, risk assessment of crude oil, as well as processing optimization of refining.

Key words: ICP-OES, metal content in crude oil, uncertainty, crude oil from middle east, metallic fingerprinting