Determination of aflatoxin B1 in sidestream cigarette smoke by immunoaffinity column extraction coupled with liquid chromatography/mass spectrometry

Aflatoxins produced by food-borne molds are known carcinogenic toxins. Aflatoxin B1 (AFB1) is reported as the most toxic of this class of mycotoxins. We have coupled immunoaffinity column extraction with LC/MS to produce a sensitive and selective approach for the study of AFB1. As AFB1 can be potentially found in tobacco it is of interest to establish whether AFB1 can be transferred from a cigarette fortified with AFB1, to the sidestream smoke. Previous studies have found that AFB1 does not transfer to the mainstream smoke. Since sidestream smoke may contain higher concentrations of some smoke components, a method was developed to analyze the sidestream smoke produced from machine-smoked cigarettes. Sidestream smoke condensates collected on Cambridge filter pads were extracted with isopropanol, then further purified using immunoaffinity extraction columns. The extracts were then analyzed by LC/MS and LC/MS/MS. An instrumental limit of detection (LOD) was established at 3.75 pg injected on column, with the limit of quantitation (LOQ) equal to 11.25 pg on column for both LC/MS and LC/MS/MS. The instrument was found to be linear from 11.25 pg to 150 pg (r > 0.995.) Precision ranged from 4.2% to 8.4% at the LOQ, while accuracy ranged from 0.53% to 1.33%. The immunoaffinity extraction method LOD was determined to be 100 pg fortified onto the Cambridge filter. The LOQ was 350 pg. The average recovery of the AFB1 from the Cambridge pad was 82.9% over the range of 100-1000 pg fortified onto the pad. AFB1 was not detected in unfortified cigarettes. A transfer experiment, fortifying cigarettes at 1 μg/cigarette determined that AFB1 was transferred only slightly from the burning cigarette to the sidestream smoke. The mean percent transfer was 0.087%.