Research Section
The pH of tobacco smokeLe pH de la fumée de tabacDer pH-Wert von Tabakrauch

https://doi.org/10.1016/0015-6264(74)90327-7Get rights and content

Abstract

The pH of tobacco smoke is a determining factor in its acute toxicity. With a rise in pH above 6·2, the smoke contains increasing amounts of unprotonated nicotine, the most toxic form of this agent. The pH was determined by puffing smoke over a highly sensitive combination electrode. Measured were the pH of the total mainstream smoke of some domestic, foreign and experimental cigarettes, as well as of some cigars and little cigars. The pH of individual puffs of cigarettes made from Bright tobacco and blended tobacco decreased slightly, from pH 6·3 to 5·6, with increasing puff number. The pH of puffs of cigars and little cigars increased from about pH 6·5 to above 7·5. The pH of smoke from cigarettes made from Bright tobacco varieties increased significantly as the height of the leaf position on the stalk increased. Total nitrogen, total alkaloids and total volatile bases of the tobacco showed a high degree of correlation with the pH of the mainstream smoke. Data on sidestream smoke are also presented. The findings of this study are discussed with regard to tobacco-smoke toxicity and inhalability.

Résumé

Le pH de la fumée de tabac est un facteur déterminant de la toxicité aiguë de celle-ci. Quand son pH s'élève au-dessus de 6,2, la fumée contient des quantités croissantes de nicotine non protonée, c'est-à-dire sous sa forme la plus toxique. On a déterminé le pH en soufflant la fumée pardessus une électrode combinée très sensible. On a mesuré ainsi le pH de tout le courant de fumée principal de quelques cigarettes de marques nationales et étrangères, ainsi que de cigarettes expérimentales et de quelques cigares et cigarillos. Le pH de bouffées individuelles de cigarettes fabriquées avec du tabac “Bright” et des mélanges de tabac a légèrement diminué de 6,3 à 5,6, à mesure que le hombre de bouffées augmentait. Le pH des bouffées des cigares et des cigarillos a augmenté d'environ 6,5 à plus de 7,5. Le pH de la fumée de cigarettes fabriquées avec différentes variétés de tabac “Bright” a augmenté significativement avec la hauteur de la position de la feuille sur la tige.

On a constaté une corrélation étroite entre les teneurs totales en azote, en alcalo'ides et en bases volatiles du tabac et le pH du courant de fumée principal. L'article contient aussi des données relatives au courant de fumée secondaire. Il commente les résultats des essais en ce qui concerne la toxitité et l'inhalabilité de la fumée de tabac.

Zusammenfassung

Der pH-Wert von Tabakrauch ist ein bestimmender Faktor für seine akute Toxizität. Mit einer Zunahme des pH-Werts über 6,2 enthält der Rauch zunehmende Mengen unprotonierten Nikotins, der toxischsten Form dieser Substanz. Der pH-Wert wurde dadurch bestimmt, dass der Rauch über eine hochempfindliche Kombinationselektrode geblasen wurde. Gemessen wurde der pH-Wert des gesamten unverdünnten Rauchs einiger im Lande und im Ausland hergestellter und von Versuchszigaretten sowie einiger Zigarren und Zigarillos. Der pH-Wert einzelner Züge yon Zigaretten aus hellem Tabak und Tabakmischung nahm mit zunehmender Zahl der Züge geringfügig von pH 6,3 bis 5,6 ab. Der pH-Wert von Zügen an Zigarren und Zigarillos stieg von etwa pH 6,5 auf über 7,5. Der pH-Wert des Rauchs von Zigaretten aus hellen Tabaksorten stieg signifikant, wenn die Höhe der Blattstellung am Pflanzenstengel zunahm. Gesamtstickstoff, Gesamtalkaloide und flüchtige Gesamtbasen des Tabaks zeigten einen hohen Grad der Korrelation mit dem pH-Wert des unverdünnten Rauchs. Daten von luftverdünntem Rauch sind ebenfalls angegeben. Die Ergebnisse dieser Untersuchung werden hinsichtlich der Toxizität und Inhalierbarkeit von Tabakrauch besprochen.

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