Study On The Tobacco-specific Nitrosamines(TSNA) And Their Precursors In Different Flue-cured Tobacco Genotypes

The tobacco-specific nitrosamines(TSNAs) were highly carcnoigenic components in tobacco. Previous researches had proved that nitrate, nitrite and alkaloids were their precursors and tobacco genotype was very important influencing factor on TSNAs. How to determinate them and ascertain the relationship between genotype and contents of TSNAs and their precursors were necessary.Nitrate, nitrite and alkaloids were quantified using ultraviolet spectrophotometer while NNN, NAT, NAB and NNK in flue-cured tobacco leaves were separated and determinated by gas chromatography with a N-P detector in this paper.The changes in TSNAs, nitrate,nitrite and alkaloids among different flue-cured tobacco genotypes were thoroughly investigated. Significant differences were discovered not only in NNN, NAT, NAB, NNK and total TSNAs concentrations but also in nitrate, nitrite and alkaloids among different flue-cured tobacco genotypes. Significant differences were also found in concentrations of TSNA and their precursors between two groups of flue-cured tobacco. The correlation of nitrite with NNN,nitrite with NNK,nitrite with total TSNA was significant respectively. The highest correlation coefficient was for the correlation of nitrate with nitrite. The correlations of nitrate with TSNA and alkaloids with TSNA were not significant. The concentrations of TSNA and their precursors in different parents and their F, hybrids were studied. The genetic characters of TSNA and their precursors were also inferred preliminarily. Because the contents of TSNA, nitrite and nitrate in F, hybrids were lower than those in their parents, maybe we could take advantage of F, hybrids to reduce the contents of TSNA, nitrite and nitrate in tobacco leaves.