QUANTITATIVE METHOD FOR DETERMINING THE ORGANIC ACID CONTENT OF CRUDE OIL

A method for analysing a crude oil to determine the amount of organic acid compounds contained in the crude oil comprising: extracting the organic acid compounds from a sample of crude oil to form an extract comprising the organic acid compounds and determining the amount of the extracted organic acids; dissolving the extract in a polar solvent to form a solution of the extracted organic acid compounds; introducing a sample of the solution of the extracted organic acid to an apparatus comprising a reversed phase liquid chromatography (LC) column and a mass spectrometer (MS) arranged in series wherein the reversed phase LC column contains a hydrophobic sorbent and the mobile phase for the LC column comprises a polar organic solvent; separating the organic acid compounds in the LC column of the LC-MS apparatus and continuously passing the separated organic acid compounds from the LC column to the MS of the LC-MS apparatus to ionize the organic acid compounds and to obtain a chromatogram with mass spectral data over time for the ionized organic acid compounds; determining the area(s) under the peak(s) in an extracted ion chromatogram derived from the mass spectral data assigned to one or more organic acid compounds; determining the amount of the organic acid compound(s) in the sample by comparing the area under the peak(s) assigned to the organic acid compound(s) with the area under a peak in an extracted ion chromatogram assigned to a specific amount of a standard organic acid compound; and extrapolating from the amount of the organic acid compound(s) in the sample to provide the total amount of the organic acid compound(s) in the extract.