Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Abstract

Abstract. Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry is a data-independent analytical method that records the fragmentation patterns of all the compounds in a sample. This study shows the implementation of atmospheric pressure photoionization with two-dimensional (2D) Fourier transform ion cyclotron resonance mass spectrometry. In the resulting 2D mass spectrum, the fragmentation patterns of the radical and protonated species from cholesterol are differentiated. This study shows the use of fragment ion lines, precursor ion lines, and neutral loss lines in the 2D mass spectrum to determine fragmentation mechanisms of known compounds and to gain information on unknown ion species in the spectrum. In concert with high resolution mass spectrometry, 2D Fourier transform ion cyclotron resonance mass spectrometry can be a useful tool for the structural analysis of small molecules.

Tandem mass spectrometry determination of the putative structure of a heterogeneous mixture of Lipid As isolated from the lipopolysaccharide of the Gram‐negative bacteria Aeromonas liquefaciens SJ‐19a

“…The ESI‐MS analysis of the mixture of LipA s was also conducted with an FTICR mass spectrometer in order to produce spectra with high mass resolution. Because FTICR‐MS is based on a time measurement and because the trapped ion frequencies are independent of the kinetic energy, this technique provides the highest resolving power and mass accuracy currently available, thus allowing the elemental composition of all the produced ions to be determined . As expected, this ESI‐MS analysis (–ve ion mode) of lipid A of A. liquefaciens SJ‐19a displayed an incomplete biosynthesis as illustrated by the multiple deprotonated molecules observed.…”

“…Please note that, in this study, we have never encountered doubly charged ions. [30][31][32][33][34][35][36][37][38] In this study, we have used low-energy collision-induced dissociation mass spectrometry (SORI-CID-MS/MS) with a Fourier transform ion cyclotron resonance mass spectrometer to establish the MS/MS fragmentation routes. In this section, only the different product ions obtained by SORI-CID-MS/MS will be discussed.…”

“…[30][31][32][33][34][35][36][37][38] There are thus many more collisions with much lower kinetic energy than in the collision cell (q) of the QqQ mass spectrometer. In addition, in the ICR mass spectrometer, the only ion that is being excited is the deprotonated molecule, [30][31][32][33][34][35][36][37][38] and once it dissociates the product ion that is formed is not further energized. In the case of the QqQ mass spectrometer, however, it is apparent that in the q collision cell, the product ions have time to collide, gain energy, and to fragment further, since all the product ions are accelerated through the q cell.…”

2D FT-ICR MS of Calmodulin: A Top-Down and Bottom-Up Approach

“…Different algorithms for the de-noising of 2D mass spectra have been developed [20,21] and are now applied to all contemporary 2D-FT-ICR MS spectra, and as a result scintillation noise no longer represents a significant problem to 2D-FT-ICR MS spectra. The potential of 2D FT-ICR MS as an analytical method for the structural analysis of small molecules has been recently demonstrated on cholesterol, showing the possibility for the technique to differentiate various fragmentation pathways and interrogate detected species [22]. 2D IRMPD FT-ICR MS has also been used for the analysis of peptides derived from tryptic digestion of commercially available collagen, which was not readily achievable with traditional 1D MS/MS [23] and for an ECD/ IRMPD comparative study for proteomics, using digested cytochrome c as a model [24].…”

Two‐dimensional mass spectrometry in a linear ion trap, an in silico model

“…De‐noising algorithms have been developed in order to reduce the effects of scintillation noise in 2D mass spectra . 2D MS has been successfully applied to the analysis of small molecules as well as in bottom‐up and top‐down proteomics . In 2D MS, the correlation between precursor ions and their products is fully multiplexed, which enables the differentiation, for example, of product ion patterns between two precursor ion species with different charge states but with overlapping isotopic distributions .…”