- Journal Details
- Format
- Journal
- eISSN
- 2719-9509
- First Published
- 01 Jan 1992
- Publication timeframe
- 4 times per year
- Languages
- English
Search
- Open Access
Limitations in the Statistical Analysis of Normalised Cigarette Smoke Analyte Yield per Milligram of Nicotine Yield
Page range: 617 - 626
Abstract
Yields of selected mainstream smoke analytes expressed per milligram of nicotine yield (nicotine ratio) and ceilings on these ratios have been proposed by WHO as part of future cigarette product regulation. This paper describes the different approaches required for precision assessment, depending on whether yields or nicotine ratios are being studied. The widely used approach of assessment of yield precision is to perform a collaborative study using a standardised method. However, for assessment of ratio precision the measurement of smoke analyte and smoke nicotine yields are often not carried out on the same set of cigarettes (unpaired) due to analytical constraints and therefore the statistical approach described in ISO 5725 is inappropriate due to the various replicate combinations. In this paper, the precision of ratios was computed with unpaired measurements for NNN and nicotine yield data for the CM6 monitor test piece and the Kentucky Reference 1R5F cigarette carried out during a collaborative study in 2011 (1). A sampling technique, based on the draw of the most representative ratios, has been used to evaluate the range of both estimated repeatability and reproducibility under the ISO smoking regime that might be expected when comparing data between different laboratories. This statistical evaluation highlighted that a robust estimate of repeatability and reproducibility could not be determined for ratios obtained with unpaired measurements, using the method defined by ISO5725-2.
- Open Access
A Comprehensive Study on Triacylglycerols in Tobacco Leaves Using Liquid Chromatography and Atmospheric- Pressure Chemical-Ionization Mass Spectrometry
Page range: 627 - 637
Abstract
Triacylglycerols in tobacco leaves were investigated to further understand their compositional and metabolic differences among various tobacco leaves and their changes during the curing processes. Non-aqueous reverse-phase chromatography for efficient separation of triacylglycerols and atmospheric-pressure chemical-ionization mass spectrometry for their detection were selected for quantitative analysis. For measuring their absolute amounts, authentic triacylglycerols comprised of the same fatty acids were introduced to generate calibration curves and to quantify the analytes. A validation study using the combination of appropriate separation and authentic triacylglycerols produced very good results in terms of linearity (> 0.999), limit of detection (3-4 ng), limit of quantification (10-15 ng) and recovery ratio (80-120%). The quantification of triacylglycerols in tobacco leaves and a subsequent principal component analysis clarified for the first time their compositional and metabolic differences among various tobacco leaves.
- Open Access
Assessment of Cigarette Smoking in Epidemiologic Studies
Page range: 638 - 648
Abstract
The assessment of cumulative exposure based on collecting information on the history of active cigarette smoking has been and is being undertaken in a variety of ways. While a very detailed assessment may be required for studies with a focus on particular aspects of smoking behavior and history, comparability of measurements and results across studies remains a primary concern. Addressing the problem of heterogeneity of exposure assessment across studies can be achieved by a core set of questions that cover the major dimensions of cigarette smoking, and yet comply with current criteria used for defining smoking history and status. In studies where no very high level of exposure assessment is required or where smoking is not the major subject of investigation, a practical standardized core set of questions appears to be of considerable value, in particularwith regard to making results more comparable across studies.
- Open Access
Evaluation of Several Minor Alkaloid Levels in Tobacco with Separation of R- and S-Nornicotine
Page range: 649 - 659
Abstract
The chiral separation of minor alkaloids from tobacco is of interest because R and S isomers of these compounds have differences in their physiological activity. This difference is also reflected in the physiological properties of tobaccospecific