title: Identification of carbohydrates by matrix-free material-enhanced laser desorption/ionisation mass spectrometry.
abstract: Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) is a sensitive mass spectrometric technique which utilises acidic materials as matrices for laser energy absorption, desorption and ionisation of analytes. These matrix materials produce background signals particularly in the low-mass range and make the detection and identification of small molecules difficult and nearly impossible. To overcome this problem this paper introduces matrix-free material-enhanced laser desorption/ionisation mass spectrometry (mf-MELDI-MS) for the screening and analysis of small molecules such as carbohydrates. For this purpose, 4,4'-azo-dianiline was immobilised on silica gel enabling the absorption of laser energy sufficient for successful desorption and ionisation of low molecular weight compounds. The particle and pore sizes, the solvent system for suspension and the sample preparation procedures have been optimised. The newly synthesised MELDI material delivered excellent spectra with regard to signal-to-noise ratio and detection sensitivity. Finally, wheat straw degradation products and Salix alba L. plant extracts were analysed proving the high performance and excellent behaviour of the introduced material.
authors.affiliation: Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens-University Innsbruck, Innrain 52a, 6020 Innsbruck, Austria.
authors.forename: Muhammad Ahsan
authors.initials: MA
authors.lastname: Hashir
authors.forename: Guenther
authors.initials: G
authors.lastname: Stecher
authors.forename: Rania
authors.initials: R
authors.lastname: Bakry
authors.forename: Saowapak
authors.initials: S
authors.lastname: Kasemsook
authors.forename: Bernhard
authors.initials: B
authors.lastname: Blassnig
authors.forename: Isabel
authors.initials: I
authors.lastname: Feuerstein
authors.forename: Gudrun
authors.initials: G
authors.lastname: Abel
authors.forename: Michael
authors.initials: M
authors.lastname: Popp
authors.forename: Ortwin
authors.initials: O
authors.lastname: Bobleter
authors.forename: Guenther K
authors.initials: GK
authors.lastname: Bonn
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D002241:Carbohydrates / Q000032:analysis* / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D001391:Azo Compounds; D002241:Carbohydrates