title: Laser desorption/ionization mass spectrometry of lipids using etched silver substrates.
abstract: Silver-assisted laser desorption/ionization mass spectrometry can be used for the analysis of small molecules. For example, adduct formation with silver cations enables the molecular analysis of long-chain hydrocarbons, which are difficult to ionize via conventional matrix-assisted laser desorption ionization (MALDI). Here we used highly porous silver foils, produced by etching with nitric acid, as sample substrates for LDI mass spectrometry. As model system for the analysis of complex lipid mixtures, cuticular extracts of fruit flies (Drosophila melanogaster) and worker bees (Apis mellifera) were investigated. The mass spectra obtained by spotting extract onto the etched silver substrates demonstrate the sensitive detection of numerous lipid classes such as long-chain saturated and unsaturated hydrocarbons, fatty acyl alcohols, wax esters, and triacylglycerols. MS imaging of cuticular surfaces with a lateral resolution of a few tens of micrometers became possible after blotting, i.e., after transferring lipids by physical contact with the substrate. The examples of pheromone-producing male hindwings of the squinting bush brown butterfly (Bicyclus anynana) and a fingermark are shown. Because the substrates are also easy to produce, they provide a viable alternative to colloidal silver nanoparticles and other so far described silver substrates.
authors.affiliation: University of Münster, Institute for Hygiene, Robert-Koch-Str. 41, 48149 Münster, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schnapp
authors.affiliation: University of Münster, Institute for Hygiene, Robert-Koch-Str. 41, 48149 Münster, Germany; University of Münster, Institute of Inorganic and Analytical Chemistry, Corrensstr. 30, 48149 Münster, Germany; NRW Graduate School of Chemistry, University of Münster, Münster, Germany.
authors.forename: Ann-Christin
authors.initials: AC
authors.lastname: Niehoff
authors.affiliation: University of Münster, Institute for Hygiene, Robert-Koch-Str. 41, 48149 Münster, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Koch
authors.affiliation: University of Münster, Institute for Hygiene, Robert-Koch-Str. 41, 48149 Münster, Germany; University of Münster, Interdisciplinary Center for Clinical Research (IZKF) Münster, Domagkstr. 3, 48149 Münster, Germany. Electronic address: Klaus.dreisewerd@uni-muenster.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Dreisewerd
mesh_terms: D000818:Animals; D001516:Bees / Q000737:chemistry; D004331:Drosophila melanogaster / Q000737:chemistry; D007834:Lasers; D008055:Lipids / Q000737:chemistry / Q000302:isolation & purification*; D053768:Metal Nanoparticles / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D008055:Lipids; C586932:colloidal silver; D012834:Silver
keywords: Blotting; Cuticular lipids; Laser desorption/ionization mass spectrometry; MS imaging; Saturated hydrocarbons; Silver substrate