title: Modified MALDI MS fatty acid profiling for bacterial identification.
abstract: Bacterial fatty acid profiling is a well-established technique for bacterial identification. Ten bacteria were analyzed using both positive- and negative-ion modes with a modified matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) approach using CaO as a matrix replacement (metal oxide laser ionization MS (MOLI MS)). The results show that reproducible lipid cleavage similar to thermal in situ tetramethyl ammonium hydroxide saponification/derivatization had occurred. Principal component analysis showed that replicates from each organism grouped in a unique space. Cross validation (CV) of spectra from both ionization modes resulted in greater than 94% validation of the data. When CV results were compared for the two ionization modes, negative-ion data produced a superior outcome. MOLI MS provides clinicians a rapid, reproducible and cost-effective bacterial diagnostic tool.
authors.affiliation: Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA. kvoorhee@mines.edu
authors.forename: Kent J
authors.initials: KJ
authors.lastname: Voorhees
authors.forename: Kirk R
authors.initials: KR
authors.lastname: Jensen
authors.forename: Casey R
authors.initials: CR
authors.lastname: McAlpin
authors.forename: Jon C
authors.initials: JC
authors.lastname: Rees
authors.forename: Robert
authors.initials: R
authors.lastname: Cody
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ubukata
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Cox
mesh_terms: D001419:Bacteria / Q000737:chemistry* / Q000145:classification*; D005227:Fatty Acids / Q000737:chemistry* / Q000302:isolation & purification; D058889:Molecular Typing / Q000379:methods*; D025341:Principal Component Analysis; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D005227:Fatty Acids
keywords: MALDI MS; MOLI MS; bacterial diagnostics; fatty acid profiling; metal oxides