Determination of Trace Amounts of Dibenzothiophenes in Diesel Fuels by HPLC-MS/MS Methods

A new approach has been proposed to determining dibenzothiophenes in diesel fuels by HPLC-MS/MS with electrospray ionization. The developed method is based on the preliminary derivatization of the target compounds through their interaction with aliphatic alcohols in the presence of trifluoromethanesulfonic acid, resulting in the formation of fixed-charge derivatives. These derivatives undergo predictable fragmentation processes, involving the elimination of an alkene from the resulting cation, which allows for their detection by selected reaction monitoring. It has been demonstrated that this analytical method provides low limits of detection for the target compounds, making it suitable for analyzing fuels meeting Euro 5 standards.