Evaluation of Carbonyl Collection Methods in Electronic Cigarette Aerosol
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Authors
Martinez, Bianca Lee
Issue Date
2023
Type
Thesis
Language
Keywords
carbonyls , collection media , DNPH Cartridge , DNPH Filter , electronic cigarettes , impingers
Alternative Title
Abstract
Popularity of electronic cigarettes (e-cigarettes) has been growing rapidly. Harmful compounds have been reported in e-cigarettes aerosols including carbonyls, such as the human carcinogens formaldehyde and acetaldehyde. Current standard method testing e-cigarette carbonyl emissions were adopted from conventional cigarette testing method. However, while carbonyls in conventional cigarette smoke found mostly in gas phase, it was reported that a large fraction of carbonyl compounds in e-cigarette aerosols could be in the particle phase. Since standard carbonyl testing methods (i.e., impinger method) are not designed to quantitatively capture particulates, there are discrepancies in e-cigarette carbonyl emissions reported by studies using different sampling methods. This study assesses carbonyl collection methods for the emissions from different e-cigarette devices to provide a standardized testing method.To address the gas and particle-bound carbonyl discrepancy, the three most frequently used methods were tested: 2,4- Dinitrophenyl hydrazine (DNPH) silica impregnated cartridge (C), DNPH- coated glass fiber filter (DF), and impinger (I). Glass fiber filter (GF) was also used to estimate the particle-bound carbonyl fraction. The sampling media were combined as follows: I-I, GF-I-I, C, DF-C, and GF-C. For sample collection, two e-cigarettes ‘pod’ (i.e., JUUL) and ‘mod’ type at different flows were used. Collected samples were analyzed using high-performance liquid chromatography with photodiode array detection (HPLC-PDA Arc 2690 with a 2998 photodiode array detector, Waters, MA, USA).
Carbonyl emissions varied between methods at different flows. For both devices, the highest emissions were measured with C and DF-C. I-I measured similar emissions for JUUL, but significantly lower for mod. For example, mod formaldehyde emissions measured with C were 0.11 ± 0.08 and 0.12 ± 0.08 µg/puff for 1 liter per minute (LPM) and 1.5 LPM, respectively. The I-I method, however, indicated 0.02 ± 0.01 and 0.03 ± 0.01 µg/puff, 33% and 40% lower than C at the same respective conditions. This discrepancy between the C and I-I methods generally followed the amount of liquid aerosol produced by the device. While C and DF-C were similar for formaldehyde, C indicated JUUL acetaldehyde emissions that were 46% lower than those measured with DF-C, while for mod they were close to each other. This could be due to the larger particle-bound fraction of acetaldehyde and the smaller particles produced by JUUL that are apparently less effectively caught by the cartridge relative to the larger mod particles. For total aerosol –hence gas and particle –, the C and DF-C provides the best approach.
In conclusion, it has been shown that the standard method (i.e., I-I) underestimates the carbonyl emissions because of its design to capture gas phase in the e-cigarette aerosol. However, as different studies have shown and as the e-cigarette market increases and new –bigger and powerful – products are developed, the necessity for refinement and advancement arises. Because of these reasons, it is recommended that the standard method is not used for e-cigarette aerosol sampling.