Mass Spectrometry, GCMS, and HPLC

Carrabba, In Situ Identification and Analysis of Automotive Paint Pigments Using Line Segment Excitation Raman Spectroscopy I Inorganic Topcoat P/gments, Journal of Forensic Sciences 46 (2001), 1053-1069. 

Mass spectrometry using alternative ionization and sample preparation methods are employed in ink and paint analysis. The oldest of these techniques is based on pjnrolysis of the sample (typically, a paint) prior to its introduction into the GC. Detectors for PyGC are and FID. Pyrolysis patterns can be examined in the same way accelerant patterns are (Chapter 10), but increasingly, GCMS is preferred over FID. Pyrolysis is, by definition, destructive, but the sample size is reasonably small, and recently a micropyrolysis GCMS has been developed and applied to photocopier toners and paint. A laser is focused on the sample through a microscope, and the pyrolysis vapor product is directed into the GCMS system. The pattern of the pyrolyzates and chemical composition 

Because many dyes and pigments are not amenable to GC, HPLC methods have been explored as an alternative. This makes sense in light of the relationship of HPLC to TLC, still a staple of colorant analysis. However, the lack of specificity in a detector system has been a limitation, and consequently, HPLC has been used in the same way as pyrolysis GC and peak or pattern matching. 

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