Application of Tandem Mass Spectra for the Peaks of Isotope Pattern in the Elemental Composition Assignment of Product Ions

Abstract

AbstractFor an ion of known formula, there are some ambiguous formulas with respect to its product ions in tandem mass spectrometry in many cases. Researchers determined them mainly by high resolution mass spectrometer combing database searching. Here, we presented an innovative method to enhance the assignment possibility of the elemental composition of the product ion by exploiting the tandem mass spectra of isotopic peaks from the precursor ion such as [M+H+1]+, [M+H+2]+ and [M+H+3]+. This approach involved a process of excluding low match formulas for product ion stepwise until the final formula with the highest match. It also facilitated the deduction of the fragmentation pathway for the precursor ion in tandem mass spectrometry. The isotopic proportions of product ions possessed a good repeatability. Additionally, this method could be performed fast and conveniently on variety of instruments, which offers an alternative determination tool for the elemental composition of product ion in tandem mass spectrometry.