Use of Derivatization for Detecting Dibenzothiophene Oxidation Products by Soft Ionization Mass Spectrometry

A new approach to detecting dibenzothiophene-5,5-dioxides by soft mass spectrometry methods has been developed. This method involves the chemical modification of target compounds with phenols in the presence of trifluoroacetic anhydride to form organic salts. The cations of these salts are easily desorbed under matrix-assisted laser desorption/ionization (MALDI) conditions and extracted by electrospray ionization (ESI). Upon collisional activation, the derivatization products eliminate the aryl oxy substituent from the sulfur atom, enabling the detection of derivatization products through selected reaction monitoring.