Tandem mass spectrometry approaches for recognition of isomeric compounds mixtures

Abstract

The present review aims to collect the published literature pertaining the recognition of isobaric compounds (isomers or stereoisomers) using the features of tandem mass spectrometry (MS) experiments without any chromatographic separation or chemical modification (derivatization or isotopic enrichment) of the analytes. MS/MS methods possess high selectivity, wide dynamic range and high throughput capabilities. Generally, tandem MS has limited capability for distinguishing isomers that fragment similarly. However, some MS/MS methods have been developed and positively applied to isomers discrimination. Among the literature on this topic, the applications that fit on the review subject can be summarized as follow: (1) chiral discrimination by the kinetic method, (2) the use energy‐resolved tandem mass spectra and the survival yield (SY) representation, (3) the kinetics evaluation of the ion‐molecule interaction and (4) the postprocessing mathematical algorithm to resolve the isomers in MS/MS signal.

Recent Advances in Separation and Analysis of Chiral Compounds

“…In general, MS identification of molecules by m / z values is unable to discriminate isomers. Even by tandem MS with commonly used fragmentation modes, enantiomers are also difficult to discriminate. , Nevertheless, several emerging MS methods, including chemical derivatization, kinetic method, ion mobility-mass spectrometry (IM-MS), and circular dichroism–laser MS, are employed to directly detect enantiomers without the combination of separation techniques. These methods are appropriate for an analysis system incompatible with the separation process, such as samples with a small volume or compounds with a short life.…”

“…The kinetic method is another major approach to discriminate enantiomers. Generally, it utilizes different signal abundance of diastereomers or their product ions for enantiomer discrimination. ,, Unlike special m / z values, difference in signal abundance is more easily achieved because most diastereomer pairs present different reaction rates during their formation or fragmentation. So, universal methods to transform enantiomers to diastereomers are necessary for the kinetic method.…”

Simultaneous Degradation Study of Isomers in Human Plasma by HPLC-MS/MS and Application of LEDA Algorithm for Their Characterization

“…All of these procedures are usually molecule-specific and can rarely be extended to other compounds. Nevertheless, in the last two decades, many MS/MS strategies have been developed to solve this problem by allowing the characterization and quantification of isomers and/or isobars in mixtures via a standardized approach, applicable to different compounds [ 11 ]. Among these strategies, the most promising and interesting for a widespread application in the recognition of isomers are based on (1) energy-resolved tandem mass experiments [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ] and (2) kinetics of the ion-molecule interaction [ 20 , 21 , 22 ], even if the latter are limited to the use of the ion trap.…”

Detection, Quantification, and Isomer Differentiation of Per- and Polyfluoroalkyl Substances (PFAS) Using MALDI-TOF with Trapped Ion Mobility

“…Contrary to all linear legacy PFCA examined thus far, PF-3,7-DMOA's dominant ion signal appeared to be [M−CO 2 H] � rather than [M−2F−CO 2 H] � . Due to the significant difference in ion fragment formation, EIM filtering seemed challenging to interpret, however, utilizing these "diagnostic fragment" intensities can allow for identification of isomers based on a ratio of intensities, 35 which will be explored in future investigations.…”