Inhalation remains the most popular method of cannabis consumption. In addition to traditional combustion methods like cannabis cigarettes (i.e., joints), electronic vaporizer cartridges have given cannabis smokers a new method of inhaling cannabinoids. The physical components of the cartridge devices themselves have been implicated as a potential source of metals exposure, but it is not known to what extent these metals might migrate into the inhalable vapor. Due to the nonpolar nature of the aerosol mixture created from cannabis vapor cartridges, traditional aqueous-based capture methods used in e-cigarette or tobacco cigarette studies for analysis of metals are insufficient. In this study, different aerosol collection methods including a conventional impinger condensing capture method, glass-free tubing condensation method and hybrid combination of impinger and tubing were compared. To optimize the collection of the nonpolar aerosol mixtures, various impinger solvent combinations including organic and acidic aqueous solvents were also studied.  The components of vaporizer cartridges and their aerosol were collected and analyzed for 10 different metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb and Sn) using an optimized and validated ICP-MS method.  In addition to the model system,  different randomly-purchased cannabis cartridges from a Washington State retailer were analyzed to compare the elemental profiles. The aerosol from non-metal heating sources for vaping and combusting cannabis products were compared.  The leaching of metals into the concentrate during ambient temperatures as well as after several vaping cycles was explored. This study demonstrates the importance of nonpolar solvent as part of the aerosol collection to increase the recovery of metals.   Results also indicate Chromium, Copper, Nickel, as well as smaller amounts of lead migrate both into the cannabis oil and the inhaled vapor phase, resulting in exposures that could rise to levels of concern.  As states like Colorado- and others to inevitably follow-plan to test emissions from cannabis concentrates, it will be important to include more than the standard As, Cd, Hg, and Pb to the list of regulated metals.

Aerosol Collection Methods and Heavy Metals Analysis for Inhaled Cannabis Products

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.