Simultaneous analysis of 22 volatile organic compounds in cigarette smoke using gas sampling bags for high-throughput solid-phase microextraction

Abstract

Quantifying volatile organic compounds (VOCs) in cigarette smoke is necessary to establish smoke-related exposure estimates and evaluate emerging products and potential reduced-exposure products. In response to this need, we developed an automated, multi-VOC quantification method for machine-generated, mainstream cigarette smoke using solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS). This method was developed to simultaneously quantify a broad range of smoke VOCs (i.e., carbonyls and volatiles, which historically have been measured by separate assays) for large exposure assessment studies. Our approach collects and maintains vapor-phase smoke in a gas sampling bag, where it is homogenized with isotopically labeled analogue internal standards and sampled using gas-phase SPME. High throughput is achieved by SPME automation using a CTC Analytics platform and custom bag tray. This method has successfully quantified 22 structurally diverse VOCs (e.g., benzene and associated monoaromatics, aldehydes and ketones, furans, acrylonitrile, 1,3-butadiene, vinyl chloride, and nitromethane) in the microgram range in mainstream smoke from 1R5F and 3R4F research cigarettes smoked under ISO (Cambridge Filter or FTC) and Intense (Health Canada or Canadian Intense) conditions. Our results are comparable to previous studies with few exceptions. Method accuracy was evaluated with third-party reference samples (≤15% error). Short-term diffusion losses from the gas sampling bag were minimal, with a 10% decrease in absolute response after 24 h. For most analytes, research cigarette inter- and intrarun precisions were ≤20% relative standard deviation (RSD). This method provides an accurate and robust means to quantify VOCs in cigarette smoke spanning a range of yields that is sufficient to characterize smoke exposure estimates.

Figure 1

Change in absolute response for ethylbenzene, 2,5-dimethylfuran, and nitromethane using bags fitted with butyl Orings, shown as filled symbols with a solid line, and silicone O-rings, shown as open symbols with a dashed line, for a 3R4F research cigarette vapor phase sample analyzed over a 5 day period.

Figure 2

Pearson correlations calculated from VOC deliveries from University of Kentucky research cigarette 3R4F smoked under ISO conditions and scatter plots including both 1R5F (gray) and 3R4F (black) research cigarettes smoked using the ISO regimen.