Rapid detection of toxic compounds in tobacco smoke condensates using high-resolution 1H-nuclear magnetic resonance spectroscopy

Abstract

In 2012, the FDA Tobacco Products Scientific Advisory Committee published a list of 93 harmful and potentially harmful constituents (HPHCs) of tobacco products and tobacco smoke. This list includes many of the “Hoffmann analytes”—the most frequently cited substances regarding the negative health effects of cigarette smoking. Proposed changes to US tobacco product regulation require reporting of HPHC concentrations in smoke. Fit-for-purpose analytical methods for measurement of HPHCs are a priority for regulatory agencies and the tobacco industry, but the chemical diversity of these substances dictates labor-intensive analyses by established techniques. Here, a semi-quantitative analysis of organic compounds on the Hoffmann list was developed using high-resolution proton nuclear magnetic resonance (HR ¹H NMR). The data acquisition protocol was validated and used to build a database of analytes in methanolic tobacco smoke condensate (TSC) of Kentucky 3R4F research cigarettes. Among 33 Hoffmann analytes amenable to NMR measurement, 20 were detected directly in TSC. For the 13 undetected substances, fortification experiments were conducted to identify the concentrations at which they were detectable. Among 34 further FDA HPHCs analyzed, 13 were detectable in 3R4F TSC via overspiking experiments. The chemical shifts of these 13 compounds plus the 20 Hoffman analytes establish a database of 33 smoke toxicants measureable in a single NMR analysis. This approach is compatible with standardized smoke collection procedures and allows rapid and consistent measurement of the selected substances in TSC. It will facilitate the chemical evaluation of large numbers of TSC samples with relatively high throughput and acceptable results reproducibility.