Mass Spectrometric Characterization of Organosulfur Compounds Using Palladium(II) as a Sensitivity-Enhancing Reagent

Abstract

Electrospray ionization/ mass spectrometry (ESI/MS) experiments were performed on several polyaromatic sulfur heterocycles (PASH) in the presence of Pd(II) in order to promote charge transfer and radical cation formation. Critical experimental parameters, i.e., Pd(II)/organosulfur mole ratio, the effect of polyaromatic hydrocarbon interferences and sample solution flow rate, and MS2 collision energy, were optimized. PASH compounds in a spiked hydrogenated oil were then identified to determine matrix effects. Selected peaks from a PASH-enriched aromatic fraction obtained from the heavy distillate of an Arabian crude were then analyzed in order to demonstrate the applicability of the method.