Simultaneous Temperature Measurements and Aerosol Collection During Vaping for the Analysis of Δ9-Tetrahydrocannabinol and Vitamin E Acetate Mixtures in Ceramic Coil Style Cartridges

Abstract

Incidence of e-cigarette, or vaping, product use-associated lung injury (EVALI) has been linked to the vaping of tetrahydrocannabinol (THC) products to which vitamin E acetate (VEA) has been added. In this work we vaped THC/VEA mixtures at elevated power levels using a variety of ceramic coil vaping cartridges and a commercially available vaping device, while simultaneously measuring temperature and collecting the vaporized condensate. The collected vapor condensate was analyzed for evidence of VEA decomposition by GC/MS, GC/FT-IR/MS, and LC-APCI-HRMS/MS. Mean temperature maxima for all examined cartridges at the selected power exceeded 430°C, with a range of 375-569°C, well beyond that required for thermal decomposition of VEA. The percent recovery of VEA and Δ⁹-THC from the vaporized mixture in six cartridges ranged from 71.5 to 101% and from 56.4 to 88.0%, respectively. Analysis of the condensed vaporized material identified VEA decomposition products duroquinone (DQ), 1-pristene, and durohydroquinone monoacetate (DHQMA); a compound consistent with 4-acetoxy-2,3,5-trimethyl-6-methylene-2,4-cyclohexadienone (ATMMC) was also detected. The concentration of DQ produced from vaporization of the THC/VEA mixture in one cartridge was found to be 4.16 ± 0.07 μg per mg of vapor condensate.

Keywords: EVALI; ceramic coil; temperature; vaping; vitamin E acetate; Δ9 -tetrahydrocannabinol.

FIGURE 1

Diagram of vaping apparatus (not to scale) for temperature monitoring and condensed vapor collection.

FIGURE 2

Thermocouple placement inside of a black-market ceramic coil cartridge containing Δ⁹-tetrahydrocannabinol with 1.5 Ω resistance and applied battery voltage of 3.7 V (A) Near the bottom of the cartridge. (B) Slightly below the bottom of the ceramic coil. (C) Inside the ceramic coil near the center.

FIGURE 3

Maximum temperature measured (n = 3) for five cartridges at battery voltage settings of 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, and 6.0.

FIGURE 4

TIC of the unvaped THC and VEA-containing E-liquid (A) compared to TICs of the post-vaped E-liquids from cartridges C1-C6 (B–G), respectively. No peaks from 7.8 to 18 min.

FIGURE 5

GC/FT-IR/MS TIC (A) and AC (B) of the post-vape E-liquid from cartridge C5 along with the TIC (C) and AC (D) of a duroquinone standard.

FIGURE 6

GC/FT-IR/MS mass spectrum of the peak at 5.30 min in the suspect chromatogram from cartridge C5 (A) and corresponding IR spectrum (B). Mass spectrum of the peak at 5.30 min in the duroquinone chromatogram (C) and corresponding IR spectrum (D).

FIGURE 7

Peak areas, normalized to the cartridge with the largest peak area for each compound, measured in the vaped samples for duroquinone (using the LC-MS EIC of m/z 165.0910), putatively assigned ATMMC (using the LC-MS EIC of m/z 207.1016), and putatively assigned DHQMA (using the LC-MS EIC of m/z 149.0962), reported as the average of three injections. Error bars represent two standard deviations. The measured recovery of VEA for each cartridge is shown above each cluster in the graph for reference.