title: Direct detection of fatty acid ethyl esters using low temperature plasma (LTP) ambient ionization mass spectrometry for rapid bacterial differentiation.
abstract: Low temperature plasma mass spectrometry (LTP-MS) was employed to detect fatty acid ethyl esters (FAEE) from bacterial samples directly. Positive ion mode FAEE mass spectrometric profiles of sixteen different bacterial samples were obtained without extraction or other sample preparation. In the range m/z 200-300, LTP mass spectra show highly reproducible and characteristic patterns. To identify the FAEE's associated with the characteristic peaks, accurate masses were recorded in the full scan mode using an LTQ/Orbitrap instrument, and tandem mass spectrometry was performed. Data were examined by principal component analysis (PCA) to determine the degree of differentiation possible amongst different bacterial species. Gram-positive and gram-negative bacteria are readily distinguished, and 11 out of 13 Salmonella strains show distinctive patterns. Growth media effects are observed but do not interfere with species recognition based on the PCA results.
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: J Isabella
authors.initials: JI
authors.lastname: Zhang
authors.forename: Anthony B
authors.initials: AB
authors.lastname: Costa
authors.forename: W Andy
authors.initials: WA
authors.lastname: Tao
authors.forename: R Graham
authors.initials: RG
authors.lastname: Cooks
mesh_terms: D001419:Bacteria / Q000737:chemistry* / Q000145:classification*; D015373:Bacterial Typing Techniques / Q000191:economics / Q000379:methods*; D003080:Cold Temperature; D004952:Esters / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis*; D013058:Mass Spectrometry / Q000191:economics / Q000379:methods*; D025341:Principal Component Analysis
chemical_list: D004952:Esters; D005227:Fatty Acids