(425l) Investigation of the Potential of the ICP-Qqq for the Analysis of Petroleum Fractions

Intensive studies have been dedicated to trace and ultra trace metals determination in petroleum products in the recent years. The need of the petroleum industry in this field is related to exploitation activities and exploration : contamination during oil production and refining (e.g. prevention of catalyst poisoning, corrosion and pollution control), and geochemical characterization of source rocks and basins in order to identify geochemical biomarkers in oil-oil or oil-source rock correlation. The existence of metals in fossil fuels was first established by Alfred Treibs in the 1930s [1]. Trace metals are incorporated into petroleum fractions as organometallic compounds (e.g. geoporphyrins) initially present in the crude oil [2] or added during the various processes of refining [3], but also as inorganic components originating from formation and production of water (e.g. contamination of Ba and As), and mineral matter (e.g. trace elements in clay minerals) [4]. Their concentration are always in the mg/kg or even µg/kg levels but low levels of certain metals can have drastic effects as a contaminant. Conventionally, ICP techniques are used [5] and allows sufficient detection limit for most of the cases of the petroleum industry. The inherent high sensitivity of ICP-MS detection together with isotopic ratio capabilities opens new fields of applications in petrochemistry or geochemistry of petroleum products, but the introduction of organic substances is not that easy as this technique was not initially designed for organic samples analysis and specific configuration of sample introduction systems are required in order to minimize organic solvent load into the ICP plasma. Moreover, specific polyatomic interferences are disturbing the spectra due to the massive presence of carbon and oxygen within the plasma. These interferences are solved with the use of a collision/reaction chamber or the use of high resolution ICP/MS [6].

The recent commercialisation of a triple quad ICP/MS by Agilent, specifically dedicated for heavy matrices analysis might be an interesting alternative to solve polyatomic interferences with petroleum fractions and attain lower detection limit. This contribution will present the result obtained with such a system compared to high resolution ICP/MS for various element and matrices tested.

[1] Treibs, A., “Porphyrins in coal”, Anal. Chem., Vol. 520, 1935, pp. 144-151.

[2] Caumette G., Lienemann C.-P., Merdrignac I., Bouyssiere B., Lobinski R., Element speciation analysis of petroleum and related materials, J. Anal At. Spectrom., 24, (2009), 263-276

[3] Chainet F., Le Meur L., Lienemann C.-P., Ponthus J.,Courtiade M., Donard O.F.X, Characterization of silicon species issued from PDMS degradation under thermal cracking of hydrocarbons: Part 2 -Liquid samples analysis by a multi-technical approach based on gas chromatography and mass spectrometry, Fuel, 116, (2014), 478-89

[4] Filby, R.H., “Origine and nature of trace elements species in crude oil, bitumens and kerogen: implications for correlation and other geochemical studies”, in: J. Parnell (Ed.), Geofluids: Origin, Migration and Evolution of Fluids in Sedimentary Basins, Geol. Soc. Sp. Pub., Vol. 78, 1994, pp. 203-221.

[5] Sánchez R., Todolí J.-L; Lienemann C.-P., Mermet J.-M., Determination of trace elements in petroleum products by Inductively Coupled Plasma techniques: a critical review, Spectro Chimica Acta Part B, 88, (2013), 104-26

[6] Pohl P., Dural D., Vorapalawut N., Merdrignac I, Lienemann C.-P.,  Carrier H., Grassl B., Bouyssiere B., Lobinski R., Multielement molecular size fractionation in crude oil and oil residue by size exclusion microchromatography with high resolution inductively coupled plasma mass spectrometric detection (HR ICP MS), J. Anal At. Spectrom., 25, (2010), 1974-7