The Detection of Delta 9-tetrahydrocannabinol in the Breath of Human Subjects

Delta 9-Tetrahydrocannabinol (THC) was detected in breath of human subjects by gas liquid chromatography/mass spectrometry (GC/MS) up to twelve minutes after smoking marijuana. A number of adsorbents were tested for THC entrapment and subsequent detection (Tenax-GC, ethanol, 0.75 N ethanolic KOH, Amberlite resin XAD-2, and Sephadex G-10). All of these gave poor recoveries. The decay rate of breath THC was much faster than that of plasma THC and there was very poor correlation between breath THC and plasma THC. We conclude that the detection of breath THC is probably due to that emanating from the surface of the mouth and respiratory system.