Helmut Oberpriller

Biosensor technology for the detection of illegal drugs I: objectives, preparatory work, and drug enrichment

In a joint project of Deutsche Aerospace, Boehringer Mannheim and the University of Potsdam portable devices for the detection of illegal drugs, based on biosensor technology, are being developed. The concept enrichment of the drug from the gas phase and detection by immunological means. This publication covers the description of our objectives, preparatory work and results concerning enrichment of drugs from the gas phase. Vapor pressures of cocaine and cannabinoids have been determined. A test gas generator has been constructed which allows for reproducible preparation of cocaine concentrations between 2 ng/l and 2 pg/l. Coupling of a thermodesorption unit with GC/MS has been established for reference analysis. As another analytical tool, an ELISA with a lower detection limit of about 0,5 pg cocaine/assay has been developed. Applying fleece-type adsorbers, enrichment factors for cocaine in the range of 105 have been realized. No significant interference was found with potentially disturbing substances.

New separation device that allows fast gas chromatography of large samples

Gaschromatography (GC) is a widespread method to separate components in complex mixtures. The separation in the gasphase follows three main principles: - separation by molecular sieves where the molecules are selected by their size - separation on solid phases using adsorption forces - separation on liquid films (stationary phases) using different solubilities of the molecules in the liquid phase. Normally the mixtures are injected as a vapour or liquid (which is vaporized in the injectorblock) on a GC-column. The components are transported by the mobile phase (carrier gas) through the column which is packed with solid carrier particles coated with a liquid film.