Multielement analysis of petroleum samples by laser ablation double focusing sector field inductively coupled plasma mass spectrometry (LA-ICP MS)

A method was developed for the direct analysis of petroleum samples. A silica gel plate, commonly used in thin layer chromatography, was impregnated for 30 min with a sample solution and analyzed by laser ablation-ICP MS. The use of a doubly focusing sector field mass analyzer allowed the demonstration of the absence of carbon-related polyatomic interferences. Matrix suppression effects, common in nebulization-based sample introduction, were absent which enabled quantitation by external calibration. The detection limits were in the low ng g(-1) range. The method was validated by the analysis of NIST 1084a and 1085b certified reference materials (wear metals in lubricating oils) and applied to the analysis of crude oil and asphaltene samples.