||Collection and Interpretation of Level 1 IR and LRMS Data.
Gaskill, Jr., Alvia ;
Gutknecht, William F. ;
||Research Triangle Inst., Research Triangle Park, NC. Systems and Measurements Div.;Industrial Environmental Research Lab., Research Triangle Park, NC.
Mass spectroscopy ;
Infrared spectroscopy ;
Chemical analysis ;
Spectroscopic analysis ;
Low resolution mass spectroscopy
||Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy.
The report gives results of an evaluation of approaches to measurement and interpretation of infrared (IR) and low resolution mass spectra (LRMS) taken by four EPA contractors, following Level 1 environmental assessment program guidelines. The evaluation involved supplying each contractor with test spectra and samples for analysis and interpretation. Using IR, the contractors identified 55-85 percent of the structural moieties present in the various samples or indicated by the various test spectra, with 85 percent being approximately the maximum attainable. Error sources in IR measurement included analyst-to-analyst variation in signal location of + or - 5-10 wave numbers and failure to optimize signal intensity through proper loading of the salt plates or KBr pellets. IR interpretation errors disclosed were errors of omission and assignment. The contractors identified 50-90 percent of the compound classes represented using LRMS. LRMS interpretation errors disclosed were failure to find molecular ions, reporting molecular ions as fragment ions and vice versa, incorrectly identifying molecular ions, and incorrectly assigning ions to homologous series.