Ethyl carbamate in Swedish and American smokeless tobacco products and some factors affecting its concentration

Abstract

BackgroundWe are interested in comparing the levels of harmful or potentially harmful constituents in Swedish and American smokeless tobacco products (STPs). We report here the concentrations of the IARC Group 2 A (probable human) carcinogen ethyl carbamate (EC) in seventy commercial STPs from the US and Sweden, representing 80–90% of the market share of the major STP categories in these countries. We also examine the effects of various additives, processing and storage conditions on EC concentrations in experimental snus samples.ResultsEC was determined from aqueous extracts of the STPs using ultra performance liquid chromatography tandem mass spectrometry (UPLC/MS/MS). EC was undetectable (< 20 ng/g wet weight basis WWB) in 60% of the commercial STPs, including all the chewing tobacco (CT), dry snuff (DS), hard pellet (HP), soft pellet (SP), and plug products. Measurable levels of EC were found in 11/16 (69%) of the moist snuff (MS) samples (average 154 ng/g in those samples containing EC) and 19/32 (59%) of the Swedish snus samples (average 35 ng/g). For the experimental snus samples, EC was only observed in ethanol treated samples. EC concentrations increased significantly with ethanol concentrations (0–4%) and with storage time (up to 24 weeks) and temperature (8 °C vs 20 °C). EC concentrations were lower at lower pHs but were unaffected by adding nitrogenous precursors identified from food studies (citrulline and urea), increasing water content or by pasteurisation. Added EC was stable in the STP matrix, but evaporative losses were significant when samples were stored for several weeks in open containers at 8 °C.ConclusionsEC was found in measurable amounts only in some moist STPs i.e. pasteurised Swedish snus and unpasteurised US MS; it is not a ubiquitous contaminant of STPs. The presence of ethanol contributed significantly to the presence of EC in experimental snus samples, more significantly at higher pH levels. Sample age also was a key determinant of EC content. In contrast, pasteurisation and fermentation do not appear to directly influence EC levels. Using published consumption rates and mouth level exposures, on average STP consumers are exposed to lower EC levels from STP use than from food consumption.Electronic supplementary materialThe online version of this article (10.1186/s13065-018-0454-x) contains supplementary material, which is available to authorized users.

The composition of contemporary American and Swedish smokeless tobacco products

“…For the Swedish products previously published data on sodium and chloride ion contents and pH values [12], and ash contents [11] are repeated here together with new information in the form of analytical variability (standard deviations). In addition, new data are presented here for mean and SD values for reducing and total sugars, glycerol and propylene glycol contents of these products, as well as pouch weights of the P snus products.…”

“…For the US products, with MS, Plug, CT, HP and SP products new data are presented here for nicotine contents; the other content data have been published previously [11, 12]; although analytical variability data for these previously reported measurements are presented here for the first time. With DS products new data are presented for nicotine, and for reducing and total sugars; other data for DS have been reported previously [11, 12].…”

“…The latter suggests that sugar decomposition during oven drying does not make a major contribution to tobacco weight loss under these conditions. The differences between BAT oven moistures and Karl Fischer waters were also significantly (p < 0.05) and negatively correlated with ammonia [12] (R = − 0.39), nicotine (R = − 0.48) and ash (R = − 0.395).…”

“…For example, the method for Karl Fischer water analysis was reported by McAdam et al [9]. Methods for nicotine, pH, reducing and total sugars, glycerol and propylene glycol, sodium and chloride ions were described by McAdam et al [12]. NIR water and ash content methods were reported by McAdam et al [11].…”

“…carcinogenic to humans [1, 2], there is growing acceptance that different product styles can offer different levels of health risk in line with their toxicant contents [3]. This has prompted a series of analyses of different STP styles for a wide range of toxicants and carcinogens, including tobacco specific nitrosamines (TSNA) [1], metals [4, 5], volatile aldehydes [6], polycyclic aromatic hydrocarbons (PAH) [7, 8], hydrazine [9], acrylamide [10], radioisotopes [11], ethyl carbamate [12] and coumarin and angelica lactones [13].…”