title: Matrix-Free UV-Laser Desorption Ionization Mass Spectrometry as a Versatile Approach for Accelerating Dereplication Studies on Lichens.
abstract: The present study examined the suitability of laser desorption/ionization time-of-flight mass spectrometry (LDI-MS) for the rapid chemical fingerprinting of lichen extracts. Lichens are known to produce a wide array of secondary metabolites. Most of these compounds are unique to the symbiotic condition but some can be found in many species. Therefore, dereplication, that is, the rapid identification of known compounds within a complex mixture is crucial in the search for novel natural products. Over the past decade, significant advances were made in analytical techniques and profiling methods specifically adapted to crude lichen extracts, but LDI-MS has never been applied in this context. However, most classes of lichen metabolites have UV chromophores, which are quite similar to commercial matrix molecules used in matrix-assisted laser desorption ionization (MALDI). It is consequently postulated that these molecules could be directly detectable by matrix-free LDI-MS. The present study evaluated the versatility of this technique by investigating the LDI properties of a vast array of single lichen metabolites as well as lichen extracts of known chemical composition. Results from the LDI experiments were compared with those obtained by direct ESI-MS detection as well as LC-ESI-MS. It was shown that LDI ionization leads to strong molecular ion formation with little fragmentation, thus, facilitating straightforward spectra interpretation and representing a valuable alternative to time-consuming LC-MS analysis.
authors.affiliation: Université de Rennes 1, UMR CNRS 6226 PNSCM, 2 Avenue du Professeur Léon Bernard, 35043 Rennes, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Le Pogam
authors.affiliation: Université d'Angers, EA 921 SONAS/SFR 4207 QUASAV, 16 Boulevard Daviers, 49100 Angers, France.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schinkovitz
authors.affiliation: Université de Rennes 1, UMR CNRS 6226 PNSCM, 2 Avenue du Professeur Léon Bernard, 35043 Rennes, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Legouin
authors.affiliation: Université de Rennes 1, UMR CNRS 6226 PNSCM, 2 Avenue du Professeur Léon Bernard, 35043 Rennes, France.|Université Paul Sabatier Toulouse 3, 118 Route de Narbonne, 31062 Toulouse, France.
authors.forename: Anne-Cécile
authors.initials: AC
authors.lastname: Le Lamer
authors.affiliation: Université de Rennes 1, UMR CNRS 6226 PNSCM, 2 Avenue du Professeur Léon Bernard, 35043 Rennes, France.
authors.forename: Joël
authors.initials: J
authors.lastname: Boustie
authors.affiliation: Université d'Angers, EA 921 SONAS/SFR 4207 QUASAV, 16 Boulevard Daviers, 49100 Angers, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Richomme
mesh_terms: D008011:Lichens / Q000737:chemistry* / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization