Matrix-suppressed laser desorption/ionisation mass spectrometry and its suitability for metabolome analyses.
Matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry was investigated for the simultaneous detection of several metabolites, as applicable to global metabolite analysis (metabolomics). The commonly employed organic matrices alpha-cyano-4-hydroxycinnamic acid and 3,5-dihydroxybenzoic acid, in both the crystalline and ionic liquid forms, were investigated. The employment of a low matrix-to-analyte molar ratio suppressed matrix peaks and was effective in detecting all the metabolites with a unique mass in a 30-metabolite synthetic cocktail, albeit to varying degrees. These matrix-suppressed laser desorption/ionisation (MSLDI) analyses were performed in the positive ion mode, and metabolites were detected as the protonated [M+H]+, sodiated [M+Na]+ or potassiated [M+K]+ species. The spectral signals were dominated by basic metabolites. It was possible to detect components of a synthetic cocktail when it was spiked quantitatively into a microbial extract, demonstrating the feasibility of using the technique for detecting metabolite signals in a complex biological matrix. However, analyte suppression effects were noted when the relative proportion of one analyte was allowed to increasingly dominate the others in a mixture. The implications of the findings with respect to applications in metabolomic investigations are discussed.
Vaidyanathan
Seetharaman
S
School of Chemistry, The University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD, UK. s.vaidyanathan@manchester.ac.uk
Gaskell
Simon
S
Goodacre
Royston
R
D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism; D003373:Coumaric Acids / Q000737:chemistry; D003460:Crystallization; D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism; D062385:Hydroxybenzoates / Q000737:chemistry; D007202:Indicators and Reagents; D004364:Pharmaceutical Preparations / Q000737:chemistry / Q000378:metabolism*; D012118:Resorcinols; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D000596:Amino Acids; D003373:Coumaric Acids; D062385:Hydroxybenzoates; D007202:Indicators and Reagents; D004364:Pharmaceutical Preparations; D012118:Resorcinols; C007175:alpha-cyano-4-hydroxycinnamate; C076950:alpha-resorcylic acid