PURGE-AND-TRAP GC FOR THE FORENSIC ANALYSIS OF LIPSTICK

In forensic investigations, lipstick smears can frequently provide use ful information about the linkage between a person and a crime scene. Although several methods, such as GC and TLC in combination with solve nt extraction, have been usually applied to lipstick analysis, a simpl e and sensitive method for lipstick smears has been required in forens ic science laboratories. This report describes the application of purg e and trap (P & T)/GC to trace the amounts of lipsticks. P & T samplin g was carried out with a Curie-Point head-space sampler. The optimum i nstrumental conditions were determined based on the results of experim ents on the recoveries using a standard solution containing dodecane, acenaphtene, nonadecane, methyl myristate and methyl stearate, as foll ows: purging conditions, 150 degrees C, 10 min; trap temperature, -10 degrees C; purging flow rate, He 20 ml/min. The reproducibility of thi s method ranged from 1.2 to 2.7% (relative standard deviation), and th e minimum amount of lipstick sample required for the analysis was 0.1 mg. This method was applied to lipstick samples from 11 manufacturers and allowed us to discriminate all samples without any interference by substrata, such as clothes and cigarette tips, on which the lipstick adhered. P & T/GC can be useful for forensic discrimination of lipstic ks.