Detection of Cannabidiol on Glass Surfaces Following Vaporization

Cannabis is the most used recreational drug worldwide, and with its steady legalization and decriminalization, there is a need for research to better understand how it affects users as well as non-users in order to provide information for evidence-based policies. Second-hand cannabis smoke and vapor can lead to third-hand exposure, where residual smoke pollutants remain on surfaces following exposure. Similar to tobacco, second-hand exposure from cannabis smoke and vapor has been described in the literature. However, there is need for further research on cannabis third-hand exposure. The purpose of this study is to investigate if CBD can be detected on a glass surface following exposure to cannabis vapor. CBD-rich hemp was used as opposed to THC-rich “drug-type” cannabis due to legal restrictions on research using THC and to the school environment in which these experiments were conducted. Glass panels were exposed to cannabis vapor in increments of 1, 5, 10, and 20 minutes. The glass sections were swabbed, and methanol extraction was used to extract the CBD from the swabs. Furthermore, the persistence of the CBD residue on the glass was investigated through delayed collection. The process of delayed collection involved allowing the glass panels to sit at room temperature for varying amounts of time following cannabis exposure. The elapsed times tested were 0, 6, 12, 24, 48, 72, 120, 168, 336, and 504 hours. Samples underwent both Duquenois-Levine color test and Gas chromatography mass spectroscopy (GCMS) examination. The Duquenois-Levine color test successfully detected CBD deposition for glass exposed for 20, 10, and 5 minutes at 6 inches from the vapor source. However, the color test could not be used to detect CBD when the glass was exposed at 12 and 18 in. from the vapor source. Persistence of CBD residue could not be measured with the color test, as only samples collected immediately after exposure resulted in a positive test. GCMS data shows CBD deposition on glass exposed at 6, 12, and 18 in. from the vapor source. Furthermore, GCMS data shows that CBD residue could be detected consistently up to 72 hours after exposure when exposed for 20 and 10 minutes at 6 and 12 in. from the vapor source.