Record Display for the EPA National Library Catalog


Main Title Large Scale Evaluation of a Pattern Recognition/Expert System for Mass Spectral Molecular Weight Estimation.
Author Scott, D. R. ; Levitsky, A. ; Stein, S. E. ;
CORP Author Environmental Protection Agency, Research Triangle Park, NC. Atmospheric Research and Exposure Assessment Lab. ;National Inst. of Standards and Technology (CSTL), Gaithersburg, MD. Chemical Kinetics and Thermodynamics Div.
Publisher 1993
Year Published 1993
Report Number EPA/600/J-93/465;
Stock Number PB94-113081
Additional Subjects Mass spectroscopy ; Pattern recognition ; Organic compounds ; Expert systems ; Molecular weight ; Spectrum analysis ; Statistical analysis ; Volatile organic compounds ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB94-113081 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 13p
A fast, personal-computer based method of estimating molecular weights of organic compounds from low resolution mass spectra has been thoroughly evaluated. The method is based on a rule-based pattern recognition/expert system approach which uses empirical linear corrections which are iteratively applied to two mass spectral features to yield estimates. This technique has been extensively evaluated with 400 spectra of volatile and nonvolatile compounds of environmental and pharmaceutical interest and with 31378 high quality NIST reference spectra of compounds of molecular weight 30-500. For both sets of evaluation spectra the median and average absolute deviations were 1.5-2.0 and 13-17 daltons, respectively. Median errors for spectra with the molecular ion present were ca. twenty times lower than those without the molecular ion. The present system can rapidly produce molecular weight estimates of a wide variety of compounds with median absolute errors of 2 (average 15) daltons. Results with the 106 toxic and related training compounds show a median and average absolute deviation of 0 and 0.6 daltons.