Volume 14 (1989): Issue 3 (January 1989)

A method for the simultaneous determination of tobacco-specific nitrosamines [TSNA], N'-nitrosonornicotine [NNN], 4-(methylnitrosamino)1-(3-pyridyl)-1-butanone [NNK], N'-nitrosoanabasine [NAB] and N'-nitrosoanatabine [NAT], as well as nitrate and nitrite in tobacco leaves and processed tobacco was developed. The analytical procedure included aqueous extraction of tobacco leaves and processed tobacco respectively under alkaline conditions in the presence of an antibacterial agent and, for TSNA analysis, a further clean-up of the aqueous extract by liquid-liquid partition extraction (kieselguhr column extraction), removal of nicotine, and determination of the nitrosamines by gas chromatography In combination with chemiluminescence detection. It is demonstrated that N'-nitrosopentylpicolylamine [NPePicA] as well as N-nitrosodibenzylamine [NDBenzA] can be used for internal standardization. For clean-up two different extraction procedures can be utilized: alkaline extraction on kieselguhr / ascorbic acid extraction columns or acidic extraction on kieselguhr including prior destruction of nitrite with sodium azide. The recoveries of the internal standards were in a similar range (73-96 %) as those of the TSNA. The analysis of nitrite and nitrate was carried out according to standard analytical procedures using the alkaline aqueous extract. The determination of nitrate and nitrite showed high accuracy and reproducibility. It is demonstrated that, under the conditions described, artifact formation did not occur even when nitrite was present. The method described is specifically applicable for the simultaneous determination of TSNA and nitrate/nitrite in tobacco leaves.

The method used to determine tobacco-specific nitrosamines [TSNA], N’-nitrosonornicotine [NNN], 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone [NNK], N’-nitrosoanabasine [NAB] and N’-nitrosoanatabine [NAT], in mainstream smoke was modified. The methodology included trapping mainstream smoke in a buffer solution and on a Cambridge filter, extracting TSNA from the buffer solution and the filter with dichloromethane, clean-up procedures and analysis by GC/TEA. Extracts from both the buffer solution and the filter were cleaned up and analysed individually. The clean-up procedure included column chromatography on basic alumina and the removal of nicotine. N-Nitrosodibenzylamine [NDBenzA] which had suitable chromatographic properties was used as internal standard. N’-Nitrosopentylpicolylamine [NPePicA], a newly synthesized nitrosamine with physicochemical properties similar to the TSNA, could also be used as an internal standard. The recoveries for the buffer solution were as follows: NDBenzA 89 %, NPePicA 83 %, NNN 85 %, NNK 88 %, NAB/NAT 85 %. For the TSNA trapped on the filter the following recoveries were determined: NDBenzA 81 %, NPePicA 75 %, NNN 77 %, NNK 78 %, NAB/NAT 75 %. Parameters influencing the TSNA values in the mainstream smoke were investigated. Artifact formation of TSNA during mainstream smoke collection did not occur under standard conditions. TSNA values were greatly influenced by the puff volume, they increased with increasing puff volume. Reproducible and reliable results can be achieved in a relatively short time with the method reported.

An investigation was performed to determine optimum conditions for the generation and collection of particulate matter and carbon oxides in sidestream smoke with a cylindrical chamber of 80 mm internal diameter. The most adequate conditions were found to be 50 cm distance between the burning cone and the Cambridge filter pad and 10 l/ min air flow rate through the chamber. Under these conditions, the static burn rate was virtually the same as that without the chamber and almost constant values for condensate were obtained by replicate measurements. Furthermore, the concentration of carbon monoxide delivered to a room could be estimated by this method. But, it was not possible to estimate the concentration of smoke particles in a room by use of sidestream measurements.

From cigarettes made of different bright tobaccos but with a constant fractional volume, the following results were obtained. The rate of formation of CO was a more influential factor determining the amount of CO in mainstream smoke than the weight loss of the cigarette during puffs. From a stepwise multiple regression analysis it was found that the rate of formation of CO was mainly dependent on the potassium content of the tobacco and could be estimated from the amounts of potassium, total carbon, and lignin. The rate of formation of CO increased with a rise in combustion temperature, which in turn rose as the potassium content of the tobacco decreased.

A microwave generator and a closed-circuit wind tunnel were used to study thermoregulatory responses of tobacco leaf. Heating and cooling curves at various wind velocities showed the maximum reduction of steady-state temperature occurred at 10 cm / s. Wind gusts of high intermittency were very effective in transferring heat from leaf tissue; gust interval and dynamic equilibrium leaf temperature were found to be linearly related. Thermal-time constant and half-cooling time of a tobacco leaf were determined as a function of wind velocity under the conditions of the Newtonian law of cooling. It was determined that transpirational cooling of tobacco leaf in total darkness could occur if leaf temperature was raised above 40°C. This study confirmed that microwaves can be effectively used to study heat exchanges of flue-cured tobacco leaves in vivo under both continuous and fluctuating wind conditions.

Growth and development of seven Oriental tobacco cultivars, representing aromatic, neutral and taste type tobacco grown in Greece, were studied at Drama, Greece, during 1982 and 1983. The growing period from transplanting to flowering ranged from 65 to 80 days and was the same for both years. plant height increase followed a sigmoid curve, the number of harvestable leaves developed almost linearly with time, and total dry weight production and leaf area increase can be described by a logarithmic curve. The effect of year on all parameters was significant, but cultivar differences were consistent. Assimilation rates during the whole period ranged from 0.1 g to 3.0 g per day per plant in 1982, and from 0.1 g to 2.7 g in 1983. Dry weight distribution in the plant parts and final yield production for the cultivars tested were also recorded.

With the development of flue-cured and Burley tobacco culture in France, black root rot, caused by Chalaraelegans (Thielaviopsisbasicola), is becoming a problem. Since 1981 the Bergerac Tobacco Institute has studied the efficacy of new endotherapeutic fungicides of the triazole family. Among these, triadimenol was found to be the most effective. The treatment method consists of spraying tobacco plants with a triadimenolsolution 48 to 72 hours before transplanting. This method appears to be an economic and efficient means to control tobacco black root rot in the field. Treatment of young tobacco plants with triadimenol strongly stimulates rhizogenesis and this favours strengthening of the tobacco plants in the field.