Identifying the New and Distinctive Exposure Risks of Little Cigars

Little cigars have been rapidly growing in popularity, especially among younger smokers. However, their chemical composition has not been as well characterized as the composition of traditional cigarettes. 

Mainstream smoke from little cigars contains a mixture of compounds that can differ substantially, both quantitatively and qualitatively, from smoke produced by cigarettes. This means that users may be exposed to compounds that are new (unique to little cigars compared to traditional cigarettes) or distinctive (occurring in higher abundance compared to traditional cigarettes). Tobacco regulators and the public health community need a better understanding of the chemical composition of these and other emerging tobacco products in order to determine whether users are exposed to new or elevated risks.

Battelle researchers studied four popular little cigar products against four popular cigarette products in order to determine the new and distinctive exposures associated with little cigars. Researchers collected particulate matter samples from machine-generated mainstream smoke. After extraction with methylene chloride, the extracts were analyzed using two-dimensional gas chromatography with time-of-flight mass spectrometric detection (GC×GC-TOFMS). This method separates chemicals by two chromatographic processes. Compared to one-dimensional gas chromatography techniques, GC×GC-TOFMS improves the ability to isolate individual compounds in analysis, giving it much greater power to detect and identify unknown compounds in complex mixtures.

A novel data-processing algorithm specifically designed for use with large data sets produced by GC×GC-TOFMS was used to evaluate the data. The algorithm allowed the research team to identify new and distinctive exposure candidates.

More than 25,000 components were detected across the complete data set. Out of these, ambrox was determined to be a new exposure compound (appearing in little cigars but not traditional cigarettes), and 3-methylbutanenitrile and 4-methylimidazole were determined to be distinctive exposure compounds (appearing in greater quantities in little cigars compared to traditional cigarettes).

In addition to identifying the new and distinctive exposure compounds unique to little cigars, the study demonstrated the capability of a novel analytical approach to identify previously uncharacterized tobacco-related exposures. The same approach could be used to characterize the constituents and identify the new and distinctive exposures associated with other tobacco product classes or specific tobacco products of interest. It could also be used to characterize the constituents and identify new and distinctive components of similar food and beverage products.