Forensic analysis of lipstick samples by three different analytical techniques

Ongoing research in our labs is focused on developing a method for extracting and separating lipstick samples that are left on different mediums at the scene of a crime. Forty different lipsticks, of various colors and brands, were analyzed using thin layer chromatography (TLC), gas chromatography (GC), and high performance liquid chromatography (HPLC). The residues are extracted in a two-part process. The first step is addition of petroleum ether to remove some oils and waxes. The second step is addition of a methanol-ammonium hydroxide mixture to dissolve any dyes or other residue. After further purification the resulting mixture is filtered using a 0.20 micron syringe filter and a TLC sample is removed. The resulting solution is split into two fractions. One fraction is subject to GC analysis and the second fraction is subjected to HPLC analysis. Results will be presented on which method produces the most consistent results TLC, GC, or HPLC.