APPLICATION OF FTICR MASS SPECTROMETRY FOR THE IDENTIFICATION OF POLAR COMPOUNDS IN ITALIAN CRUDE OIL

The use of the crude oil as primary source for the energy oblige necessarily the characterization of this matrix to the aim to estimate the impact in several contexts: productive and environmental. Petroleum crude oil is a complex organic mixture, in terms of the number of chemically distinct constituents: is composed of unsaturated and saturated hydrocarbons, heteroatoms (such as N, S, and O), as well as a small percentage of metals, particularly vanadium, nickel, iron and copper. The hydrocarbon fraction can be as high as 90% by weight in the lighter oils, compared to about 70% in heavy crude oil. A majority of the heteroatom free aromatics contain paraffinic chains, naphthalene rings, and aromatic rings side by side. Heteroatomic compounds (NSO) make up a relatively small portion of crude oils, less than 15%12, but have significant implications because your presence and composition, that depend of the origin of the crude oil, can cause of positive and negative effects in the transformations process. A variety of techniques have been employed to examine the structure of these aromatic species. Compositions of the saturated hydrocarbons have been well characterized by gas chromatography mass spectrometry (Zadro et al,1985), two-dimensional gas chromatography coupled to mass spectrometry (Wang et al.,2005), high-resolution mass spectrometry (Guan et al.,1996) , and liquid chromatography mass spectrometry (Qian, 1992; Hsu et al.1991). However, comparatively little is known about the less abundant polar species or heavy crude oils, whose compositional complexity far exceeds the peak capacity of typical analytical techniques. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS) is capable of achieving the peak capacity needed to resolve individual components of a complex data matrix. In the last years FT-ICR/MS has received considerable attention for its ability to make mass measurements with a combination of resolution and accuracy that is higher than any other mass spectrometer. In particular in recent work Marshall and co-authors demonstrated the unique utility of high field (9.4 T) of Electrospray Ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR/MS) to resolve and identify the polar species found in all petroleum distillates and for the identification of compounds in crude oils without prior chromatographic separation (Qian et al, 2001). In this work we show a preliminary results obtained studying an Italian crude oil sample belonging to the well area, sited into the Viggiano countryside in the Basilicata region (Southern Italy) and the same oil after deterioration simulation, naturally occurring in the external environments (soil, water), by means of UV irradiation. The analysis were realised using ESI/FT-ICR-MS 7 T Thermo Electron installed at Basilicata University and a NANOESI/FT-ICR-MS 12 T installed at GSFNational Research Centre for Environment and Health, Institute for Ecological Chemistry, Neuherberg, Germany. The aim was to compare two instruments characterised by a different work philosophy.