Catalytic degradation of tobacco-specific nitrosamines by ferric zeolite

New strategy of using ferric zeolite ZSM-5 and Y to adsorb and catalytically degrade tobacco-specific nitrosamines (TSNA) is reported in this article. These zeolites were modified by both aqueous ion-exchange with FeSO₄ solution and wet-impregnation of Fe(NO₃)₃, and characterized by XRD, UV-vis DRS, H₂-TPR and temperature-programmed surface reaction (TPSR). Apart from laboratory tests, these samples were put into tobacco rods of cigarette to assess their real performance of reducing TSNA content in smoke, and the determination of TSNA was carried out by LC-MS/MS technique with the assistance of internal-standards. The ion-exchanged zeolites are more active than their impregnated analogs, and the ferric Y zeolite could selectively reduce 26% of total TSNA in mainstream smoke of Burley type tobacco. Catalytic breaking of the chemical bond in NNO group of nitrosamines by zeolite is the key step of decomposition of these carcinogens.