NCJ Number
113143
Journal
Crime Laboratory Digest Volume: 15 Issue: 2 Dated: (April 1988) Pages: 39-40
Date Published
1988
Length
2 pages
Annotation
To assess the feasibility of characterizing paint specimens by dual-column pyrolysis gas chromatography (PGC), five paint color groups were chosen from the chemical supplement to the 'Reference Collection of Automotive Paints.'
Abstract
The five color groups included four General Motors (GM) blue metallics, five GM green metallics, four GM light blues, nine GM orange metallics, and five Ford red metallics. Each group contained a number of paints that were visually indistinguishable in color. Examination of simultaneously generated pyrograms revealed that in all cases noticeably different pyrogram patterns were obtained on each column for each paint. The significant differences obtained offer the analyst a large number of cross-match points in conducting comparisons. With the exception of some GM orange paints, all paints could be differentiated by either column. However, seven pairs of orange paints were indistinguishable on the SPB-1 column, while three pairs could not be differentiated in the SPB-1000 column. When both columns were considered, only two paint pairs remained indistinguishable. Results suggest that dual-column PGC offers a greater degree of confidence in judging paint comparisons from pyrogram patterns. 1 note and 3 references.