title: Rapid discrimination of bacteria by paper spray mass spectrometry.
abstract: Paper spray mass spectrometry ambient ionization is utilized for rapid discrimination of bacteria without sample preparation. Bacterial colonies were smeared onto filter paper precut to a sharp point, then wetted with solvent and held at a high potential. Charged droplets released by field emission were sucked into the mass spectrometer inlet and mass spectra were recorded. Sixteen different species representing eight different genera from Gram-positive and Gram-negative bacteria were investigated. Phospholipids were the predominant species observed in the mass spectra in both the negative and positive ion modes. Multivariate data analysis based on principal component analysis, followed by linear discriminant analysis, allowed bacterial discrimination. The lipid information in the negative ion mass spectra proved useful for species level differentiation of the investigated Gram-positive bacteria. Gram-negative bacteria were differentiated at the species level by using a numerical data fusion strategy of positive and negative ion mass spectra.
authors.affiliation: Department of Chemistry and Center for Analytical Instrumentation Development, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Hamid
authors.forename: Alan K
authors.initials: AK
authors.lastname: Jarmusch
authors.forename: Valentina
authors.initials: V
authors.lastname: Pirro
authors.forename: David H
authors.initials: DH
authors.lastname: Pincus
authors.forename: Bradford G
authors.initials: BG
authors.lastname: Clay
authors.forename: Gaspard
authors.initials: G
authors.lastname: Gervasi
authors.forename: R Graham
authors.initials: RG
authors.lastname: Cooks
mesh_terms: D006090:Gram-Negative Bacteria / Q000145:classification*; D006094:Gram-Positive Bacteria / Q000145:classification*; D013058:Mass Spectrometry / Q000379:methods*; D015999:Multivariate Analysis; D010209:Paper