Electronic Cigarettes Part VIII: Vapor Analysis – Why we chose multi-sorbent thermal desorption for analyzing VOCs like acetaldehyde

In the last installment of this blog series we let you know that we were utilizing triple-sorbent thermal desorption (TD) tubes to collect electronic cigarette vapor. However, we did not tell you why, but obviously I am going to do so right now. As you may already know, Restek dabbles in the field of whole air canister sampling. So obviously we attempted to collect and analyze e-cigarette vapor with canisters. This did work fairly well and we were able to see many of the VOCs like formaldehyde, acetaldehyde, and acrolein; however, we were not able to see nicotine and glycerin. It was not clear if the nicotine and glycerin were getting stuck in the canisters and/or held up in our air preconcentrator. Regardless, we wanted to see these major constituents of e-cig vapor in our analyses. Not to mention it is very unsettling to know you are losing some compounds in your sampling/analysis train, but you do not know where.

So that is where we decided to try TD tubes. Now to be completely fair, TD tubes are not the only game in town. There are various time-integrated and real-time instruments designed for the sampling and analysis of VOCs and SVOCs; however, only a limited number of these methodologies have been applicated to e-cigarette vapor testing. In fact, an exhaustive literature search produced the following peer-reviewed manuscripts, which have attempted to characterize electronic cigarette vapor: Goniewicz et al., Kosmider, McAuley et al., and Uchiyama et al. Goniewicz et al. utilized solid adsorbent tubes for fifteen carbonyl compounds (aldehydes and ketones) and twelve VOCs. Kosmider et al. and Uchiyama et al. utilized 2,4-dinitrophenylhyrdrazine (DNPH) coated silica cartridges to capture and analyze twelve and six carbonyls, respectively. And McAuley utilized solid adsorbent tubes for benzene, toluene, ethylbenzene, and m/p xylenes (BTEX).

We chose our multi-sorbent sampling and analytical approach, because it offered the following three distinct advantages over the aformentioned cited studies:

  1. The VOCs and SVOCs were not limited to a class of compounds (e.g., carbonyls). Therefore, a variety of alkanes, alkenes, aromatics, and halogenated compounds were evaluated.
  2. The multi-sorbent approach expanded our scope well beyond the previously limited BTEX lists to hydrocarbons in the C2 to C32 range.
  3. Derivatization and/or solvent extraction was not required. Like other studies, samples were immediately (i.e., <1 min) analyzed post- sampling, and therefore there was no need to form a “stable” carbonyl-hydrazone derivative, which then had to be solvent extracted.

Overall, the current method may be well suited for the easy and rapid screening of e-cigarette vapor for a large number of VOCs and SVOCs. So now we still need to address the compounds of interest we found and concentrations encountered. Stay tuned…

 

M.L. Goniewicz, J. Knysak, M. Gawron, L. Kosmider, A. Sobczak, J. Kurek, A. Prokopowicz, M. Jablonska-Czapla, C. Rosik-Dulewska, C. Havel, P. Jacob III, N. Benowitz, Levels of selected carcinogens and toxicants in vapour from electronic cigarettes, Tob Control 23 (2014) 133.

Kosmider, A. Sobczak, M. Fik, J. Knysak, M. Zaciera, J. Kurek, M.L., Goniewicz,Carbonyl compounds in electronic cigarette vapors: effects of nicotine solvent and battery output voltage,Nicotine Tob Res 16 (2014) 1319.

T.R. McAuley, P.K. Hopke, J. Zhao, and S. Babaian, Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality, Inhal Toxicol 24 (2012) 850.

Uchiyama, K. Ohta, Y. Inaba, and N. Kunugita, Determination of carbonyl compounds generated from the e-cigarette using coupled silica cartridges impregnated with hydroquinone and 2,4-dinitrophenylhydrazine, followed by high-performance liquid chromatography, Anal Sci 29 (2013) 1219.

2 Responses to “Electronic Cigarettes Part VIII: Vapor Analysis – Why we chose multi-sorbent thermal desorption for analyzing VOCs like acetaldehyde”

  1. Justin says:

    This is a great series of blogs. Would you please consider expanding the scope of this study? Rather than focusing on the e-juice, would you please conduct an analysis on these portable vaporizers which implement a heating coil for oils and solid material? This topic is of concern to medical marijuana patients who do not use the tobacco fluids.

    Thank you.

  2. Justin says:

    I realized my last comment was kind of vague. I’m wondering how the heating elements of these vaporizers which are compatible with “e-juice” would differ from those compatible with solid substances. They may be similar enough to be composed of the same parts, but I would assume the components would be slightly different, and therefor the vapor compositions should differ as well. If the heating components are in fact different, then would be nice to see analysis on the different heating elements available; though I believe the most common is a ceramic rod with coil wrapping.

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