The demand for developing analytical protocols for the analysis of e-cigarette emissions has been rapidly increasing in recent years. A majority of methodologies currently used for the charaterization of e-cigarette aerosols are derived from approaches originaly developed for the analysis of tobacco smoke which is fundamentaly a different matrix. The objective of this study was to determine the amount of potential menthol “breakthrough” from e-aerosol in comparison to tobacco smoke using a standard Cambridge filter pad (CFP) for collection.

The analysis of mainstream menthol in tobacco smoke is routinely conducted by the collection of particulate matter onto a CFP, with the pad extracted in isopropanol. To evaluate the trapping efficiency of menthol in mainstream aerosol emissions, an impinger containing 20 mL of isopropanol was placed behind the CFP. The contents of the pad and impinger were analyzed separately in order to determine the potential amount of menthol breakthrough from the CFP.

The trapping efficiency of the CFP for menthol was found to be regime dependent and ranged from 9.31 (±1.36) % under the 80/3/30 “square profile” regime, to 5.93 (±0.43) % under a 55/3/30 “square profile” regime, to 3.51 (±0.44) % under an ISO regime. With respect to menthol in mainstream cigarette smoke, menthol breakthrough was less than 1% when smoked under either HCI or ISO puffing regimens. Based on these results, the trapping efficiency of other analytes capable of being determined using the same methodology (propylene glycol, glycerol, nicotine, glycidol, ethylene glycol, diethylene glycol) were also investigated under the more intensive regime.

Based on this limited set of analyses, menthol in e-aerosols is not completely trapped by a CFP. However, propylene glycol, nicotine and glycerol is. When the methodology is extended to include additional e-liquid specific contaminants, significant amounts (proportional to the absolute amount) of breakthrough can occur.