Pete Gibbons

By Dr Pete Gibbons, Head of Reduced-Risk Product Analysis at Hall Analytical

Hall Analytical (now part of the Element Materials Technology) is the leading UK laboratory partner for the Nicotine Reduced-Risk Product industry, with specialist knowledge in the analysis of next-generation Heated Tobacco Products (HTP). We’re proud to continue to support the R&D activities and regulatory submission data requirements of our clients, enabling them to deliver reduced-risk product alternatives for nicotine consumers in highly regulated markets.

For the harm-reduction potential of HTP to be realised, high-quality test data must be delivered, not only to regulators but also the public, to demonstrate the reduction in Harmful and Potentially Harmful Constituents (HPHCs) of the aerosol in comparison to combustible cigarettes.

To obtain a picture of the relative reduction in user exposure to HPHCs from next-generation HTP, we must conduct robust testing of the tobacco-derived aerosol in the laboratory. This can be achieved in the form of targeted analysis of well-established HPHCs from many years of tobacco research, and non-targeted screening techniques to identify unknown compounds unique to the HTP aerosol. HPHC gases are produced from the combustion of burning tobacco (fuel) in oxygen, and thermal decomposition of tobacco constituents. Oxides of carbon (CO/CO2) and nitrogen (NO/NOx) are amongst the harmful gases produced from lit cigarettes.

Carbon monoxide is usually found at elevated levels in the blood of smokers, with a number of adverse health effects occurring due to CO binding to haemoglobin to form carboxyhaemoglobin. Smokers suffering from cardiovascular disease are at heighten risk from carbon monoxide. Acute exposure to nitrogen oxides can cause local irritation to the eyes and respiratory system, whereas chronic exposure is linked to several adverse health effects on multiple organs, with increased risk-factor of cardiopulmonary mortality. So, the hazards to smokers are clear; however, next-generation HTP only heat specially manufactured tobacco components at a much lower temperature with precision heating technology. If combustion is absent, then analysis of the resultant HTP aerosol should reveal significant relative reductions of oxides of carbon and nitrogen. Indeed, literature reports indicate the relative reduction of carbon monoxide/nitrogen oxides in HTP aerosol at >90% relative to reference cigarettes, tested under laboratory conditions1. But how is analysis of gases in HTP aerosols achieved in the lab? Let’s explore the techniques available to Hall Analytical scientists.

HTP aerosol analysis presents unique challenges compared to ENDS aerosol, and potential contamination from HTP testing necessitates a dedicated laboratory, removed from our wet lab and ENDS facilities. We’ve designed our laboratory so we can test HTP under controlled conditions as prescribed in international and industry standards. For the generation and collection of HTP aerosols, we’ve worked closely with our supplier to customise an industry standard ENDS vaping machine for HTP aerosol collection applications. These modifications include customised collection of aerosol gases per device port, enabling collection of sufficient gas volume per puffing regime to accurately determine concentrations of gases of interest (CO/CO2, NO/NOx). Once the aerosol collection of the HTP is complete, the gas sample is transferred to the appropriate multi-component gas analyser. Non-Dispersive Infra-Red (NDIR) detectors are the industry standard method for measuring concentration of the gases CO and CO2, whereas measurement of NO/NOx concentration is performed using highly sensitive chemiluminescence detection (extremely selective for nitrogen oxides). Calibration of the analysers using gas standards is performed prior to analysis of HTP aerosol collections. The sample gas phase is introduced to the measuring cell under the same conditions as aerosol collection, with the same gas flow rate used during calibration. Appropriate numbers of replicate measurements are performed, dependent on the needs of our clients. The readings from analysers are recorded and observed concentrations of the targeted gases are determined. Calculations are performed as per international standard/industry guidance, and results reported following data QC checks, as per the requirements of our clients. E.g., mg/µg per HTP stick, under specified testing regime.

We hope this blog has given you an insight into how we measure some of the target gases in HTP aerosols using the latest equipment and methods at Hall Analytical, now part of the Element Materials Technology Group. We can help your business comply with regulatory and/or product testing standards. With over 10 years’ experience of Reduced-Risk Product testing, we’re recognised as the laboratory partner of choice for the nicotine product sector. Please get in contact today for a free consultation.


1 Poget, L et al. Contributions to Tobacco Research. Volume 29, No. 2, August 2020.