Musiktheater in Österreich

Reininghaus, Frieder; Ender, Daniel; Weberberger, Doris

doi:10.7767/omz.2012.67.2.79

Cited by 1 publication

(1 citation statement)

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“…Nicotine has two basic nitrogen groups in its chemical structure (p k a 1 = 3.12; p k a 2 = 8.02), and thus, it can exist in three forms, namely, free-base (Nic), monoprotonated (NicH + ), or diprotonated salt (NicH 2 + ) depending on the pH of the matrix. − This intrinsic characteristic is quite important since it affects the bioavailability of nicotine; Nic is thought to be the only form that diffuses through epithelial tissues in the human body. Thus, all else being equal, an ECIG with a higher proportion of Nic will increase the rate of uptake of nicotine by the user’s body.…”

Section: Introductionmentioning

confidence: 99%

Free-Base and Protonated Nicotine in Electronic Cigarette Liquids and Aerosols

El‐Hellani

El-Hage

Baalbaki

et al. 2015

Chem. Res. Toxicol.

100

119

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Introduction Reliable characterization of the nicotine content and emissions from electronic cigarettes (ECIGs) is crucial for product regulation. Understanding nicotine delivery, and therefore efficacy and abuse potential, from ECIG products requires quantifying the total nicotine contained or emitted, as well as the partitioning between its free-base and protonated forms. To date, studies reporting nicotine content and emissions of ECIGs have not addressed whether the reported values correspond to the total nicotine or only one of its forms, making the reported results difficult to compare across studies, or to correlate against blood exposure measurements. In this study we investigate whether nicotine in ECIGs is indeed present in more than one form, whether measurements are affected by sampling media, and report a validated method for determining total, free-base (Nic) and protonated nicotine (NicH+) in ECIG liquids and aerosol emissions. Methods We developed an analytical method based on liquid-liquid extraction coupled with GC analysis to assess the respective amounts of Nic and NicH+. The method was first verified on pH-controlled solutions (5 < pH < 10) and then was applied to several ECIG liquids and aerosols generated using a smoking machine. Results The method showed high repeatability and efficiency, and the results were in agreement with theoretical predictions based on measured pH of the standard nicotine solutions. ECIG liquids and aerosols contained both Nic and NicH+, and their relative proportions varied widely. Free-base nicotine was found to account for 18-95% of the total nicotine depending on the product in question. Conclusions The wide variation in nicotine partitioning across products suggests that studies of nicotine delivery from ECIGs should account for this factor. A convenient method for analyzing nicotine fractions in electronic cigarettes has been demonstrated.

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Section: Introductionmentioning

confidence: 99%