Evaluation of precision and accuracy of the Borgwaldt RM20S^® smoking machine designed for in vitro exposure

Abstract

The Borgwaldt RM20S^® smoking machine enables the generation, dilution, and transfer of fresh cigarette smoke to cell exposure chambers, for in vitro analyses. We present a study confirming the precision (repeatability r, reproducibility R) and accuracy of smoke dose generated by the Borgwaldt RM20S^® system and delivery to exposure chambers. Due to the aerosol nature of cigarette smoke, the repeatability of the dilution of the vapor phase in air was assessed by quantifying two reference standard gases: methane (CH₄, r between 29.0 and 37.0 and RSD between 2.2% and 4.5%) and carbon monoxide (CO, r between 166.8 and 235.8 and RSD between 0.7% and 3.7%). The accuracy of dilution (percent error) for CH₄ and CO was between 6.4% and 19.5% and between 5.8% and 6.4%, respectively, over a 10–1000-fold dilution range. To corroborate our findings, a small inter-laboratory study was carried out for CH₄ measurements. The combined dilution repeatability had an r between 21.3 and 46.4, R between 52.9 and 88.4, RSD between 6.3% and 17.3%, and error between 4.3% and 13.1%. Based on the particulate component of cigarette smoke (3R4F), the repeatability (RSD = 12%) of the undiluted smoke generated by the Borgwaldt RM20S^® was assessed by quantifying solanesol using high-performance liquid chromatography with ultraviolet detection (HPLC/UV). Finally, the repeatability (r between 0.98 and 4.53 and RSD between 8.8% and 12%) of the dilution of generated smoke particulate phase was assessed by quantifying solanesol following various dilutions of cigarette smoke. The findings in this study suggest the Borgwaldt RM20S^® smoking machine is a reliable tool to generate and deliver repeatable and reproducible doses of whole smoke to in vitro cultures.

Keywords::

• Cigarette smoke
• whole smoke
• exposure system
• smoking machine
• Borgwaldt RM20S^®
• carbon monoxide
• methane
• solanesol

Acknowledgements

The authors thank M. Gaudreau, J. Dumont, J. Verreault and M. Barber for their technical support. N. Kaur was partially funded by the National Science and Engineering Council of Canada (NSERC) and the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) as a Ph.D. candidate at the University of Montreal. The authors M. Lacasse, J.-P. Roy, J.-L. Cabral, and A. Morin acknowledge that they are employed by Imperial Tobacco Canada Limited. The authors J. Adamson, G. Errington, and M. Gaca acknowledge that they are employed by British American Tobacco. K.C. Waldron acknowledges that she is employed by University of Montreal.

Declaration of interest

This work was supported by Imperial Tobacco Canada Limited, the sponsor of the study. The sponsor participated equally with the other institutions to the study design, the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.