Record Display for the EPA National Library Catalog


Main Title Determination of Chemical Classes from Mass Spectra of Toxic Organic Compounds by SIMCA Pattern Recognition and Information Theory.
Author Scott, D. R. ;
CORP Author Environmental Monitoring Systems Lab., Research Triangle Park, NC.
Year Published 1986
Report Number EPA/600/J-86/064;
Stock Number PB86-204658
Additional Subjects Mass spectra ; Mass spectroscopy ; Hazardous materials ; Organic compounds ; Air pollution ; Alkanes ; Alkene compounds ; Aromatic compounds ; Reprints ; Toxic substances
Library Call Number Additional Info Location Last
NTIS  PB86-204658 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 12p
The low resolution mass spectra of a set of 78 toxic volatile organic compounds were examined for information concerning chemical classes. These compounds were predominately chloro- and/or bromoaromatics, -alkanes, or -alkenes, which are routinely sought at trace levels in ambient air samples using gas chromatography-mass spectrometry. The set of mass spectra of the pure compounds contained 151 different masses in the range of 35 to 256. The Shannon information content for each mass channel was calculated for the binary encoded and the full intensity spectra, using 1% of the base peak as the threshold level. The 17 masses with the highest Shannon information content were retained as a basis set (the compressed set) for SIMCA pattern recognition using principal component analysis. Examination of the inherent class structure of the compressed set of mass spectra showed a separation of the data into two major classes: aromatics and alkaenes (alkanes and alkenes). The aromatic compounds could be divided into two subclasses: chloro-and nonchloroaromatics.