Student Projects: The Forensic Institute Research Network (FIRN)

Detection of cocaine at the picogram level in an urban environment

A gas chromatographic-mass spectrometric (GC-MS) method is described capable of detecting picogram levels of cocaine. The method was used to analyse for the presence of cocaine within samples taken from internal surfaces of six public telephone booths within the central Derby city area. Analytical separations were performed using a dimethylsilicone capillary column using a ramped temperature program. The selected detection method was electron impact ionisation using selected ions with m/z of 82 and 182. Samples were collected by first swabbing the surface and then extracted using dichloromethane. Three swabbing approaches were used: a dry swab; one moistened with water and a third using a swab dipped in ethanol. The subsequent solutions were then analysed using GC-MS with a detection limit of 100 picograms for cocaine. The study showed the presence of cocaine from one booth out of the six tested. Within this booth several areas were separately swabbed and each indicated the presence of cocaine. An ethanol wetted swab detected 500 picograms of cocaine taken from the coin slot region. This study shows the utility of GC-MS for real world detection of cocaine within an urban environment.

Miss Sonica Devi; Dr ALAN-SHAUN WILKINSON, University of Derby, Room N611, Kedleston Road, Derby, DE22 1GB, UK; email a.s.wilkinson@derby.ac.uk