Characterization of Sulfides in Atmospheric Residue Fractions Using Selective Oxidation Followed by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

An improved analytical method was developed for identifying sulfide compounds from aromatic fractions in Lungu atmospheric residue (LGAR). Sulfides in residue aromatics were selectively oxidized into sulfoxides using tetrabutyl ammonium periodate (TBAP) and identified by positive-ion Electrospray Ionization Source (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Results showed that sulfides with lower polarity in LGAR aromatics could effectively ionize in ESI using this approach. Additionally, the oxidized sulfides were mainly S1 and S2 class species. The most abundant oxidation-generated sulfoxides O1S1 and O1S2 in LGAR aromatics had DBE values of 3~10 and 8~12, respectively. The S2 class species, whose condensation degree was higher than that of S1, were likely in the form of containing both cyclic sulfides and thiophenic compounds.