Recent changes in automotive paint formulation using pyrolysis gas chromatography mass spectrometry for identification

The analysis of paint fragments recovered during forensic investigations using Pyrolysis-GC/MS (PyGC-MS) has a long standing history. Pyrograms generated from intact fragments or separated layers are used to match paint evidence to known paint formulations in an effort tb narrow the scope of the search, help identify involved vehicles, and exclude others. The peaks which appear in any pyrogram of an automotive paint may be a complex mixture of polymer pyrolysate, additives, plasticizers and other ingredients, each of which has a specific function in the performance of the paint as a product. Automotive paint formulations undergo constant evolution and revision based on the needs of the industry, including appearance, longevity, repair, and economics. Recently, environmental concerns have been added to the mix, with the mandate to reduce volatile organic emissions from paints. Newer formulations may include a higher solids load, changed polymer chemistries, water-based products and the results of other new technologies. How these formulation changes present themselves when the dried paint is examined as forensic evidence is presented, together with comparisons of older formulations. (C) 1997 Elsevier Science B.V.