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.
School of Chemistry, The University of Manchester, P.O. Box 88, Sackville Street, Manchester M60 1QD, UK. s.vaidyanathan@manchester.ac.uk
Seetharaman
S
Vaidyanathan
Simon
S
Gaskell
Royston
R
Goodacre
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