Several approaches were explored to develop a high throughput procedure for relative determination of 14 different carbon-centered free radicals, both acyl and alkylaminocarbonyl type, in cigarette smoke. Two trapping procedures using 3-cyano-2,2,5,5-tetramethyl-1-pyrrolidinyloxy, or 3-cyanoproxyl radical (3-CNP) were designed for this study: a) trapping in solution and b) trapping on a solid support which was a Cambridge filter pad. Fresh whole smoke and vapor phase smoke from mainstream cigarette smoke from Kentucky Reference Cigarettes 2R4F, as partitioned via an unadulterated Cambridge filter pad, were transferred into each trapping system in separate experiments. The 3-CNP coated Cambridge filter pad approach was shown to be superior to the impinger procedure as described in this study. Gas chromatography coupled with mass selective detection (GC-MS) was employed for the first time as an alternate means of detecting several relatively highly concentrated radical adducts. Liquid chromatography tandem mass spectrometry (LC-MS/MS) with precursor ion monitoring and selected ion monitoring (SIM) was used for detecting the large array of radicals, including several not previously reported: formyl, crotonyl, acrolein, aminocarbonyl, and anilinocarbonyl radicals. Relative quantitation was achieved using as external calibration standards of 4-(1-pyrrolidino)benzaldehyde and nicotine. It was determined that the yield of carbon-centered free radicals by reference cigarette 2R4F was approximately 265 nmoles/cigarette at 35 mL puff/60 sec interval/2 sec duration smoking conditions.
Nitrogenous compounds such as amino acids and proteins are frequently analyzed in tobacco since they are considered precursors of toxicants in cigarette smoke. However, much less attention is given to other nitrogenous compounds such as amino sugars and deoxyfructosazines, although their concentration in tobacco can be equal to or even higher than that of most free amino acids. These nitrogenous compounds may contribute to the formation of toxicants in smoke, or may contribute to the sensory properties of cigarette smoke, reasons for which their analysis is important. This study describes a procedure for the analysis of adenosine, 2,5- and 2,6-deoxyfructosazines (DFs), mannosamine and glucosamine in tobacco. The analysis uses a liquid chromatographytandem mass spectrometry (LC/MS/MS) technique. Sample preparation for analysis consists of the extraction of the tobacco with a solution of 90% water and 10% methanol, followed by filtration. The separation of the analytes was done on a hydrophilic interaction liquid chromatography HILIC column using an isocratic procedure with a solvent consisting of 78% CH3CN, 22% H2O, that also contained 0.1 % HCOOH and 0.143 g/L CH3COONH4. The measurements were done using electrospray positive ionization mass spectrometric detection. The analytical procedure was validated and was proven very reliable. A number of tobaccos were analyzed, including several fluecured and Burley USA tobaccos, off-shore tobaccos, two
Oriental tobaccos, two green tobaccos, as well as tobaccos from commercial and Kentucky reference cigarettes. The ranges for the analytes per g tobacco were found between 0.4 and 20.3 µg/g for adenosine, between 0.0 and 608.5 µg/g for 2,5-DF, between 0.0 and 424.5 µg/g for 2,6-DF, between 12.5 and 415.5 µg/g for mannosamine and between 25.9 and 1885.7 µg/g for glucosamine. The study also indicated that the levels of DFs and that of the amino sugars in tobacco show a very good correlation. This correlation can be explained by the same source of the two classes of compounds, namely the reaction of (reducing) sugars and ammonia.