Method Development and Validation of an Aerosol Sampling Technique for the Analysis of Nicotine in Electronic Cigarette Aerosols.

Because of the increasing popularity of e-cigarettes, monitoring the e-cigarette market has become important for national health authorities to guarantee safety and quality. In the EU, the Tobacco Products Directive requires emission studies for e-cigarette products. The absence of industry guidelines for studying these emissions and the lack of proper validation in the literature led us to develop and validate a method using the total error approach for the determination of nicotine in e-cigarette aerosols. A commercial vaping device was used to generate aerosols, which were then collected on Cambridge filter pads and measured for nicotine concentration by UHPLC-DAD after extraction. The method was successfully validated by generating accuracy profiles, which show that the ß-expectation tolerance intervals remained below the acceptance limits of ±20%. Within-run repeatability and intermediate precision were considered acceptable since the highest RSD value obtained was below 5%. The method was applied to 15 commercial e-liquids. A complete validation of a method for the analysis of e-cigarette emissions is presented, including several parameters that impact the accuracy and reproducibility. Similar systematic approaches for method development and validation could be used for other e-cigarette emission analysis methods to ensure the reliability of the measurements.

Development and validation of a ddPCR assay to detect and quantify tobacco DNA in smoke and smokeless tobacco and tobacco-free products.

The last decade, smoke and smokeless products claiming to be tobacco-free, including herbal cigarettes and herbal shisha, became available on the European market and gained popularity. This study proposes a new digital droplet PCR (ddPCR) method, designed based on a previously developed real-time PCR (qPCR) method being currently used by the U.S. Food and Drug Administration (FDA) to specifically detect the presence of tobacco DNA in targeting a sequence from the Nicotiana tabacum nia-1 gene. To ensure a harmonized and reliable control by enforcement laboratories, both of these qPCR and ddPCR methods were then evaluated and validated for their compliance to an international standard. First, the performance of these PCR-based methods was successfully assessed as specific and sensitive, and in line with minimum performance requirements from international standard. Secondly, the transferability to external laboratory was confirmed for these PCR-based methods. Finally, the applicability of these PCR-based methods was demonstrated using 7 ground tobacco reference materials from the Tobacco Research Center (TRC) Toronto University as well as 6 commercial smokeless and tobacco-free smoke and smokeless products. Based on this study, the previously developed qPCR method was confirmed as complying with international standard, ensuring a efficient and harmonize use by enforcement laboratories for tobacco control on the European market. Moreover, this study proposed to enforcement laboratories the possibility to use a ddPCR method, enabling the simultaneous detection and absolute quantification of tobacco DNA as well as a limited impact of PCR inhibitors.