Structural analysis of leukotriene C₄isomers using collisional activation and 157 nm photodissociation

Abstract

The fragmentation of 5-hydroxy-6-glutathionyl-7,9,11,14-eicosatetraenoic acid [leukotriene C 4 or LTC 4 (5, 6)] and its isomeric counterpart LTC 4 (14, 15) were studied by low and high-energy collisional induced dissociation (CID) and 157 nm photofragmentation. For singly charged protonated LTC 4 precursors, photodissociation significantly enhances the signal intensities of informative fragment ions that are very important to distinguish the two LTC 4 isomers and generates a few additional fragment ions that are not usually observed in CID experiments. The ion trap enables MS n experiments on the fragment ions generated by photodissociation. Photofragmentation is found to be suitable for the structural identification and isomeric differentiation of cysteinyl leukotrienes and is more informative than low or high-energy CID. We describe for the first time the structural characterization of the LTC 4 (14, 15) isomer by mass spectrometry using CID and 157 nm light activation methods. (J

Structural Characterization of Gangliosides and Glycolipids via Ultraviolet Photodissociation Mass Spectrometry

“…Reilly et al reported that 157 nm UVPD of leukotrienes produced CID-like fragment ions as well as UVPD-specific diagnostic radical ions that allowed differentiation of isomers. 55 More recently Blanksby et al have demonstrated a new radical directed dissociation (RDD) method that led to intrachain fragmentation of fatty acyl groups. This approach entailed attachment of a 4-iodobenzyl group to the lipid, either by non-covalent adduction or covalent derivatization, which served as a UV chromophore at 266 nm and a radical initiator.…”

Identification of isomeric N-glycan structures by mass spectrometry with 157 nm laser-induced photofragmentation

“…Recently, we applied 15% of the normalized collision energy during photodissociation experiments to increase the fragmentation efficiency. This significantly improves the signal intensities of MS 2 stage photofragments [53]. It was of interest to study this efficiency using multiple laser shots that were employed to generate our photofragmentation spectra.…”

193 nm Ultraviolet Photodissociation Mass Spectrometry for the Structural Elucidation of Lipid A Compounds in Complex Mixtures

“…33−37 UVPD has gained widespread acceptance as a frontier higher energy MS/MS technique that rivals or in some cases outperforms conventional CID methods for both broad profiling of biopolymers and more selective chromophore-mediated approaches. 33−35,38−57 UVPD has been applied to a wide range of bioanalytes including nucleic acids, 40−43 peptides and proteins, 44−52 glycans and oligosaccharides, 53,54 and more recently lipids 55−58 and lipid A molecules. 33−37 …”