Solid-phase microextraction (SPME) is a popular sampling technique in which chemical compounds are collected with a sorbent-coated fiber and then desorbed into an analytical instrument such as a liquid or gas chromatograph. Typically, this technique is used to sample the headspace above a solid or liquid sample (headspace SPME), or to directly sample a liquid (immersion SPME). However, this work demonstrates an alternative approach where the sample is totally vaporized (total vaporization SPME or TV-SPME) so that analytes partition directly between the vapor phase and the SPME fiber. The implementation of this technique is demonstrated with polydimethylsiloxane-divinylbenzene (PDMS-DVB) and polyacrylate (PA) coated SPME fibers for the collection of nicotine and its metabolite cotinine in chloroform extracts. The most important method parameters were optimized using a central composite design, and this resulted in an optimal extraction temperature (96 °C), extraction time (60 min), and sample volume (120 μL). In this application, large sample volumes up to 210 μL were analyzed using a volatile solvent such as chloroform at elevated temperatures. The sensitivity of TV-SPME is nearly twice that of liquid injection for cotinine and nearly 6 times higher for nicotine. In addition, increased sampling selectivity of TV-SPME permits detection of both nicotine and cotinine in hair as biomarkers of tobacco use where in the past the detection of cotinine has not been achieved by conventional SPME.
In 2009, the R. J. Reynolds Tobacco Co. released a line of dissolvable tobacco products that are marketed as an alternative to smoking in places where smoking is prohibited. These products are currently available in Indianapolis, IN, Columbus, OH, and Portland, OR. This paper describes the chemical characterization of four such products by gas chromatography-mass spectrometry (GC-MS). The dissolvable tobacco products were extracted and prepared by ultrasonic extraction using acetone, trimethylsilyl derivatization, and headspace solid phase microextraction (SPME). The following compounds were identified in the dissolvables using either ultrasonic extractions or trimethylsilyl derivatization: nicotine, ethyl citrate, palmitic acid, stearic acid, sorbitol, glycerol, and xylitol. The following compounds were identified in the dissolvables using headspace SPME: nicotine, ethyl citrate, cinnamaldehyde, coumarin, vanillin, and carvone. With the exception of nicotine, the compounds identified thus far in the dissolvables are either flavoring compounds or binders. The concentration of free nicotine in the dissolvables was determined from the Henderson-Hasselbalch equation and by measuring the pH and nicotine concentration by GC-MS. The results presented here are the first to reveal the complexity of dissolvable tobacco products and may be used to assess potential oral health effects.
This paper describes the modification of an existing gas chromatographic (GC) method to incorporate simultaneous mass spectrometric (MSD) and flame ionization detection (FID) into the analysis of tobacco humectants. Glycerol, propylene glycol, and triethylene glycol were analyzed in tobacco labeled as roll-your-own (RYO), cigar, cigarette, moist snuff, and hookah tobacco. Tobacco was extracted in methanol containing 1,3-butanediol (internal standard), filtered, and separated on a 15 m megabore DB-Wax column. Post-column flow was distributed using a microfluidic splitter between the MSD and FID for simultaneous detection. The limits of detection for the FID detector were 0.5 μg/mL (propylene glycol and triethylene glycol) and 0.25 μg/mL (glycerol) with a linear range of 2-2000 μg/mL (propylene glycol and triethylene glycol) and 1-4000 μg/mL (glycerol). The limits of detection for the MSD detector were 2 μg/mL (propylene glycol and triethylene glycol) and 4 μg/mL (glycerol) with a linear range of 20-2000 μg/mL (propylene glycol and triethylene glycol) and 40-4000 μg/mL (glycerol). Significant improvement in the sensitivity of the MSD can be achieved by employing selective ion monitoring (SIM) detection mode. Although a high degree of correlation was observed between the results from FID and MSD analyses, marginal chromatographic resolution between glycerol and triethylene glycol limits the applicability of FID to samples containing low levels of both of these humectants. Utilizing MSD greatly improves the reliability of quantitative results because compensation for inadequate chromatographic resolution can be accomplished with mass selectivity in detection.
Dissolvable tobacco products are smokeless, spit-free, made from finely milled tobacco, and dissolve in the mouth of a user. In 2009, R.J. Reynolds Tobacco Co. released a line of dissolvable tobacco products in several test markets. In late 2010, the dissolvables were reformulated and several changes in their composition were determined and are reported here. Our analytical approach featured gas chromatography-mass spectrometry preceded by four separate methods for sample preparation: solvent extraction using acetone, trimethylsilyl derivatization of sugars, solid-phase microextraction of semivolatiles and liquid-liquid extraction for the quantitative analysis of nicotine. Taken together, these methods identified several changes in the formulation of the initial products and their reformulated versions. One major change in the new dissolvables is that "mellow" and "fresh" flavors have been replaced by a "mint" flavor. Additionally, the strips are no longer dominated by glycerol, but rather threitol. Total nicotine and (free nicotine) concentrations for the orbs, sticks, and strips were found to be 3.35 mg g À1 (1.242 mg g À1 ), 2.6 mg g À1 (0.850 mg g À1 ), and 2.74 mg g À1 (0.572 mg g À1 ), respectively.Total nicotine and free nicotine concentrations have significantly increased in some cases.
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