Furan Metabolites Are Elevated in Users of Various Tobacco Products and Cannabis.

Humans are exposed to furan, a toxicant and possible human carcinogen, through multiple sources including diet and tobacco smoke. The urinary metabolites of furan are derived from the reaction of its toxic metabolite with protein nucleophiles and are biomarkers of exposure and potential harm. An established isotopic dilution liquid-chromatography mass spectrometry method was used to measure these biomarkers in urine from users of e-cigarettes, cannabis, and/or combustible tobacco with/without reduced nicotine levels. Amounts of furan mercapturic acid metabolites were higher in these individuals relative to nonsmokers, indicating that they may be at risk for potential furan-derived toxicities.