Abstract
The capacity of the six isomeric dimethylphenols to act as reagent for the quantitative determination of nitrate is examined. Only 3,4-dimethylphenol proved to be suitable for the distillation method which was found to be most appropriate to tobacco. Chromatographic and spectrophotometric investigations showed that the resultant reaction products from tobacco extracts are identical with the nitro-dimethylphenols originating from pure nitrate.
The determination of tobacco nitrate by the described method is reproducible with a coefficient of variation of about 0.9 to 1.3 per cent. The results obtained by different laboratories coincided satisfactorily. Quantities of 0.1 per cent of nitrate can be determined without difficulties.
The nitrate content depends strongly on the respective variety of cured tobacco leaf and varies from 0 to 6 per cent. Dark tobaccos are particularly rich in nitrate. Nitrate is mainly found in the ribs of tobacco leaves and in the lower leaves of the tobacco plant. The maximum quantity of nitrite contained in tobacco amounts to 0.01 per cent.