title: Combining desorption electrospray ionization mass spectrometry and nuclear magnetic resonance for differential metabolomics without sample preparation.
abstract: Desorption electrospray ionization mass spectrometry (DESI-MS) and nuclear magnetic resonance (NMR) spectroscopy are used to provide data on urine examined without sample preparation to allow differentiation between diseased (lung cancer) and healthy mice. Principal component analysis (PCA) is used to shortlist compounds with potential for biomarker screening which are responsible for significant differences between control urine samples and samples from diseased animals. Similar PCA score plots have been achieved by DESI-MS and NMR, using a subset of common detected metabolites. The common compounds detected by DESI and NMR have the same changes in sign of their concentrations thereby indicating the usefulness of corroborative analytical methods. The effects of different solvents and surfaces on the DESI mass spectra are also evaluated and optimized. Over 80 different metabolites were successfully identified by DESI-MS and tandem mass spectrometry experiments, with no prior sample preparation.
authors.affiliation: Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Huanwen
authors.initials: H
authors.lastname: Chen
authors.forename: Zhengzheng
authors.initials: Z
authors.lastname: Pan
authors.forename: Nari
authors.initials: N
authors.lastname: Talaty
authors.forename: Daniel
authors.initials: D
authors.lastname: Raftery
authors.forename: R Graham
authors.initials: RG
authors.lastname: Cooks
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D016208:Databases, Factual; D004098:Dihydroxyacetone / Q000652:urine; D020723:Glucuronic Acid / Q000652:urine; D007536:Isomerism; D019344:Lactic Acid / Q000652:urine; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D025341:Principal Component Analysis; D012997:Solvents; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013499:Surface Properties; D014556:Urine / Q000737:chemistry
chemical_list: D015415:Biomarkers; D012997:Solvents; D019344:Lactic Acid; D020723:Glucuronic Acid; D004098:Dihydroxyacetone