title: Creation of libraries of recurring mass spectra from large data sets assisted by a dual-column workflow.
abstract: An analytical methodology has been developed for extracting recurrent unidentified spectra (RUS) from large GC/MS data sets. Spectra were first extracted from original data files by the Automated Mass Spectral Deconvolution and Identification System (AMDIS; Stein, S. E. J. Am. Soc. Mass Spectrom. 1999 , 10 , 770 - 781 ) using settings designed to minimize spurious spectra, followed by searching the NIST library with all unidentified spectra. The spectra that could not be identified were then filtered to remove poorly deconvoluted data and clustered. The results were assumed to be unidentified components. This was tested by requiring each unidentified spectrum to be found in two chromatographic columns with slightly different stationary phases. This methodology has been applied to a large set of pediatric urine samples. A library of spectra and retention indices for derivatized urine components, both identified and recurrent unidentified, has been created and is available for download.
authors.affiliation: Biomolecular Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899-8362, United States.
authors.forename: W Gary
authors.initials: WG
authors.lastname: Mallard
authors.forename: N Rabe
authors.initials: NR
authors.lastname: Andriamaharavo
authors.forename: Yuri A
authors.initials: YA
authors.lastname: Mirokhin
authors.forename: John M
authors.initials: JM
authors.lastname: Halket
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Stein
mesh_terms: D019343:Citric Acid / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D054852:Small Molecule Libraries / Q000737:chemistry*; D014556:Urine / Q000737:chemistry
chemical_list: D054852:Small Molecule Libraries; D019343:Citric Acid