This project focused on detecting nicotine concentrations in e-juices for electronic cigarettes. The three brands tested were samples from Vimanna Vapor (watermelon flavor), Funky Monkey (a banana-based “Funky Monkey” flavor), and Vapor Timme (Pina Colada flavor). The e-juices were prepared for analysis by taking 1 mL of e-juice and diluting to 100 mL with a mixture of 90/10 methylene chloride/methanol. The methylene chloride contained a dilute concentration of diphenhydramine at 6.98 × 10–4 M. The diphenhydramine was used as an injection standard to control for variations in manual injection (~1 µL) into the Gas Chromatograph-Mass Spectrometer (GC-MS) which was operated in Selected Ion Monitoring (SIM) mode. A calibration curve for nicotine was constructed by gathering peak area data for nicotine standards. The calibration curve spanned the concentrations of nicotine from 9.9 × 10–5 mg/mL to 0.495 mg/mL. With the curve forced through the origin, the calibration had an R2 value of 0.9806 with a slope of 6.055 × 106. The results of analyzing four brands of e-juices in various concentrations often showed statistically significant variation in the determined concentration of nicotine as compared with the stated concentration. The Funky Monkey samples analyzed were determined to have concentrations less than the Limit of Quantification (LOQ; 9.9 × 10–5 mg/mL) for the 0 mg/mL sample, 10.097 ± 0.708 mg/mL for the 10 mg/mL sample, and 20.72 ± 2.09 mg/mL for the 24 mg/mL sample. The Vapor Timme samples analyzed were determined to have concentrations of 0.110 ± 0.019 mg/mL for the 0 mg/mL sample, 12.67 ± 0.64 mg/mL for the 9 mg/mL sample, and 22.06 ± 2.19 mg/mL for the 24 mg/mL sample. The Vimanna Vapor samples analyzed were determined to have concentrations less than the LOQ for the 0 mg/mL sample, 13.41 ± 0.4 for the 12 mg/mL sample, and 23.77 ± 1.51 mg/mL for the 24 mg/mL sample. The variation in the results as compared to the stated values suggest that these concentrations are not strictly controlled. A secondary study was performed to determine the identity of several flavorings used in the e-juices by injecting a 2 μL sample of headspace into the GC-MS (operated in full scan mode). Several flavorings were identified using the mass spectra generated.

Analysis of nicotine and flavorings in e-juices used for vaping

254th National Meeting (2017)

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