GC/MS determination of pyrolysis products from diacetylmorphine and adulterants of street heroin samples

The inhalation of heroin vapors after heating on aluminium foil ("chasing the dragon") is gaining popularity nowadays among heroin users seeking to avoid the risks of parenteral drug administration. The heroin-smoking procedure was simulated under laboratory conditions by heating the samples on aluminium foil at 250 to 400 degrees C and collecting the vapors in a condenser trap. A total of 72 pyrolysis products of diacetylmorphine, street heroin, residues from aluminium foils used to smoke street heroin, typical by-products, and adulterants were detected by gas chromatography/mass spectrometry (GC/MS). About half of these compounds could be identified. Diacetylmorphine (base and salt) undergoes substantial to complete degradation. Some typical street heroin constituents, like morphine, codeine, acetylcodeine, papaverine, and caffeine, are rather heat-stable. Other compounds, like noscapine and paracetamol, are pyrolyzed to a greater extent. The principal chemical reactions leading to the formation of pyrolysis products are desacetylation, transacetylation, N-demethylation, O-methylation, ring cleavage and oxydation.