Fate of Aflatoxins in Cigarette Tobacco

Commercial non-filter cigarettes were treated with 100 µg or 300 µg of aflatoxin B₁ and smoked in a smoking machine. The 25 mm butts, the particulate phase of smoke collected on Cambridge filters, the gaseous phase of smoke, and the ashes combined from 10 cigarettes in each experiment, were tested for the presence of aflatoxins by TLC and spectrophotofluorometry. In six separate smoking experiments no trace of aflatoxin B₁ could be detected in any of the fractions examined. The crystalline aflatoxin B₁ used in these experiments was prepared by growing cultures of Aspergillus flavus on rice. The acute oral LD₅₀ (12 days) in weanling rats was 7.5 mg/kg and the acute oral LD₅₀ (7 days) in one-to-three-day old white Pekin ducklings was 0.78 mg/kg ± 0.30 mg/kg. The melting point of aflatoxin B₁ was 263-264°C, and the molar extinction coefficient (ε) was 25,000 and 13,400 at wave lengths of 361 mµ and 265 mµ, respectively. The fluorescence excitation and emission wave lengths were 363 mµ and 423 mµ, respectively