- Dettagli della rivista
- Pubblicato per la prima volta
- 01 Jan 1992
- Periodo di pubblicazione
- 4 volte all'anno
- Accesso libero
Pagine: 237 - 244
Experiments were conducted to independently determine the mainstream smoke transfer efficiency of d-nicotine and l-nicotine. Two types of cigarettes (University of Kentucky 2R1 reference cigarette and a cigarette prepared from reconstituted sheet material, TS1) were employed in the study. A chiral-gas chromatography-selected ion monitoring-mass selective detection analysis was used to separate and determine d- and l-nicotine. The two types of cigarettes were injected with varying levels of d- or l-nicotine (0-20 mg). The tobacco was removed from the nicotine-injected cigarettes and analyzed for total nicotine and d- and l-nicotine. The cigarettes were smoked under FTC (Federal Trade Commission) conditions, and the Cambridge pad extracts were analyzed for total nicotine and d- and l-nicotine. The total nicotine transfer efficiency and the transfer efficiencies of d- and l-nicotine were determined. Nicotine transfer efficiency is dependent on the type of tobacco employed in a blend and the configuration of the cigarette. As a result, the total nicotine transfer efficiency for the 2R1 cigarettes was different than for the TS1 cigarettes. Likewise, the independently measured transfer efficiencies for d- and l-nicotine were different between the two cigarettes. The transfer efficiencies of d- and l-nicotine were not found to be different within a cigarette type. The average transfer efficiency for d-nicotine in a 2R1 cigarette was determined to be 19.25%. The average transfer efficiency for l-nicotine in a 2R1 cigarette was 16.05%. The average transfer efficiency for d-nicotine in a TS1 cigarette was 10.15% and 10.65% for l-nicotine. These differences between d- and l-nicotine were determined not to be statistically significant and are of no practical consequence.
- Accesso libero
Pagine: 245 - 249
We investigated the relationship between the smoldering burn rate and the heat transfer from a burning cigarette by measuring the heat emitted by radiation and convection, separately. The net heat generated and the net heat emitted by a burning cigarette did not vary with a change of the cigarette smoldering burn rate. The total heat emitted from a statically burning cigarette was about 50% of the total combustion heat. About 50% of the heat emitted was released as radiation heat. The smoldering burn rate did not affect the total amount of heat emitted nor the ratio of radiated heat to convected heat.
- Accesso libero
Pagine: 251 - 265
An international collaborative study was performed to compare several analytical methods for the determination of nicotine in tobacco that are in current use around the world. Five nicotine methods were evaluated and compared, specifically methyl-t-butyl ether (MTBE) extraction with capillary-column gas chromatography (GC), n-hexane extraction with capillary-column GC, n-hexane extraction with packed-column GC, methanol/ammonia extraction with capillary-column GC, and aqueous extraction with continuous flow analyzer (CFA) colorimetry. A total of 37 laboratories participated in the study, with between 9 and 18 laboratories submitting data per nicotine method. Repeatability, reproducibility, and mean nicotine statistics were calculated and compared for each method. Results for reproducibility (%) and mean nicotine difference (%, relative to the mean of the three capillary-GC methods), respectively, for each method are as follows: MTBE method (2.5%, -1.40%), hexane-capillary (4.5%, +0.06%), methanol/ammonia (3.7%, +1.34%), CFA (4.4%, +4.08%), and hexane-packed (5.8%, +4.14%). Pair-wise group comparison tests with simultaneous 95% confidence intervals were used to compare the sample nicotine values between any two given methods. Eight of the ten pair-wise comparisons were statistically different at 95% confidence, the two statistically indistinguishable pair-wise comparisons being CFA vs. hexane-packed and hexane-capillary vs. methanol/ammonia. The results of this collaborative study will be useful toward the goal of standardizing on a reference method for nicotine analysis in tobacco and tobacco products.
- Accesso libero
Determination of Mercury in Mainstream Cigarette Smoke by Conventional and Amalgamation Cold Vapor Atomic Absorption Spectrometry
Pagine: 267 - 276
A method for differentiation of gas- and particulate-phase mercury in mainstream cigarette smoke was developed using electrostatic precipitation (EP) as the trap for the particulate phase and impingers containing acidic potassium permanganate solution as the trap for the gas-phase portion. The mercury collected from the gas phase was analyzed by conventional cold vapor atomic absorption spectrometry (CVAAS) and the particulate phase was analyzed by gold amalgamation CVAAS. Cigarettes were smoked under two smoking regimes, FTC (35-mL puff volume, 2 s puff duration and one puff every 60 s) and an alternative (45-mL puff volume, 2 s puff duration, one puff every 30 s and 50% of any ventilation holes blocked) currently recommended by the Massachusetts Department of Health. For the 1R4F reference cigarette smoked under the FTC smoking regime, the mercury found in the particulate phase was less than 0.2 ng/cig, compared with 4.9 ng/cig in the gas phase. By changing smoking parameters, the mercury concentration in mainstream smoke was found to change proportional to the delivery of cigarette smoke condensate (CSC) for the same type of cigarette. However, the mercury level for different types of cigarettes smoked under the same smoking parameters had no linear relationship with CSC delivery. Spiked recovery was 98% AA± 8% for gas-phase mercury and 97% AA± 2% for the particulate phase. These results indicate that the analytical method developed is suitable for the determination of mercury in mainstream smoke. For routine analytical work in a smoking laboratory, only the gas phase needs to be analyzed for determination of mercury in mainstream smoke because the amount of mercury in the particulate phase is negligible.