Identification of hydroxyl radical oxidation products of n-hexanoyl-homoserine lactone by reversed-phase high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

TitleIdentification of hydroxyl radical oxidation products of n-hexanoyl-homoserine lactone by reversed-phase high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry
Publication TypeJournal Article
Year of Publication2009
AuthorsCui, Y, Frey, RL, Ferry, JL, Ferguson, PL
JournalRapid Communications in Mass Spectrometry
Volume23
Issue8
Start Page1212
Pagination1212 - 1220
Date Published01/2009
Abstract

A reversed-phase high-performance liquid chromatography/electrospray tandem mass spectrometry method was developed for the characterization of hydroxyl radical oxidation products of N-hexanoylhomoserine lactone (C6-HSL), a member of the N-acylhomoserine lactone (AHL) class of microbial quorum-sensing signaling molecules identified in many Gram-negative strains of bacteria. Six products were identified: four with molecular weight (MW) of 213 and two with MW of 260. The characteristic product ions formed through collision-induced dissociation (CID) provided diagnostic structural information. One of the photolysis products was determined to be N-(3-oxohexanoyl)homoserine lactone (30C6-HSL), a highly active quorum-sensing signal, by comparison with a reference standard. Three structural isomers with the same mass as 3OC6-HSL were identified as acyl side chain oxidized C6-HSL (keto/enol functionalized) by accurate mass measurement and the structures of these products were proposed from CID spectral interpretation. Two structural isomers formed from concurrent oxidation and nitration of C6-HSL were also observed and their structures were postulated based on CID spectra. In addition to the six hydroxyl radical oxidation products formed from the C6-HSL precursor, five additional compounds generated from combined oxidation and lactonolysis of C6-HSL were identified and structures were postulated. Copyright © 2009 John Wiley and Sons, Ltd.

DOI10.1002/rcm.3991
Short TitleRapid Communications in Mass Spectrometry