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  • Author: G Lionetti x
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Quantitative Determination of Free and Protein-Bound Amino Acids of Tobacco

Abstract

This paper describes a method for the extraction, separation and determination of amino acids, both free and protein-bound, which are present in tobacco. The introduction of the lyophilization process and the ''cold finger'' technique made it possible to obtain a good purification of extracts which, unlike the previous methods, have been preserved for a long time. The combined use of column chromatography and mass spectrometry enabled all amino acids present to be detected. The analyses carried out on different tobacco varieties showed certain quantitative and qualitative differences in the composition of amino acids and only small quantitative variations in the composition of protein-bound amino acids

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Gas-Chromatographic Determination of the Trimethylsilyl Derivatives of Polyhydric Alcohol Humectants in Tobacco and in Tobacco Smoke

Abstract

A qualitative and quantitative procedure has been developed for the determination of humectants in manufactured tobacco by gas-chromatographic method with a flame ionization detector. It consists of extraction with methanol, concentration of the extract and treatment with Tri-Sil reagents. The operating gas-chromatographic conditions are set forth. Samples of tobacco containing glycerine, propylene glycol, diethylene glycol, triethylene glycol, 1-3 butylene glycol and sorbitol have been analysed with recoveries, for the first five ones, in the range of 95-104 %. In order to verify that each chromatographic peak corresponded to the relative glycol, with no interference by other silylated compounds, the mass spectra were obtained through the combination of gas-chromatography with mass spectrometry. The results achieved confirm, as far as tobacco is concerned, that the procedure is accurate and precise. The same method for the determination of humectants was extended to cigarette smoke. Even though this involves morecomplicated problems, as compared to tobacco, because of the presence of silylated compounds, it was found that, for certain glycols, the gas-chromatography of the trimethyl derivatives can be also used as a method of analysis. The mass spectra of some polyhydric alcohols are shown

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Determination of Residues of Eight Synthetic Pyrethroids in Tobacco by Capillary Gas Chromatography

Abstract

A method was developed for the simultaneous determination of the residues of the following eight synthetic pyrethroids and their isomers in tobacco: tetramethrin, permethrin, cyfluthrin, cypermethrin, alfamethrin, flucythrinate, fluvalinate and deltamethrin. The pesticides were extracted from ground tobacco by means of acetone:water 9:1 for 5 hours. The extract was diluted with water and partitioned into n-hexane. The organic phase was concentrated to about 1 ml and then purified by a Florisil-SPE column. The gas-chromatographic analyses were run with a gas-chromatograph Carlo Erba Series Mega HRGC 5300 equipped with a capillary column (stationary phase OV-1 - 0.10-0.15 µm film thickness, 25 m long) and a 63Ni electron-capture detector. Two different injection ports were used: split-splitless and cold split-splitless, working both with isothermal and programmed temperatures. Both the limit of detection and the limit of determination were estimated for each compound. Recoveries from fortified samples at level of 1 µgKg-1 are reported.

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Determination of Free and Bound Maleic Hydrazide Residues in Tobacco by High Performance Liquid Chromatography

Abstract

A new method is described for the qualitative and quantitative determination of both free and bound maleic hydrazide residues in tobacco leaves and cigarette filler by high performance liquid chromatography. Analyses were carried out by hydrolyzing samples of ground tobacco with 4 N hydrochloric acid for 40 minutes under reflux followed by sample chromatography, running isocratic elutions with a dilute solution of phosphoric acid. The quantitative determination of maleic hydrazide was performed by light absorption at 320 nm, by the calibration curve method. Recoveries of maleic hydrazide added to tobacco samples were greater than 90 %. The detection limit of the method, determined on ground tobacco leaves, was at least 5 ppm. The results obtained by this procedure and by the ISO standard method no. 4876 are in good accordance.

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Seminars in Tobacco Science: Terms used for Exposure to Smoke

Abstract

The Smoking Behaviour Sub Group of the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) was set up in 1996 with the aims of reviewing information relevant to smoking behaviour, publishing the reviews, identifying gaps in information and suggesting suitable studies. So far three reviews have been published by members of the sub group (1-3) and other reviews are in progress. One aspect of the subject that has become apparent to the sub group is that terms are used inconsistently in various papers on smoking behaviour. We therefore propose that the following terms and their definitions are used in the future.

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