Determination of mycotoxins in tobacco and smokeless tobacco products by liquid chromatography tandem mass spectrometry.
A LC-MS/MS method was developed for the determination of mycotoxins (aflatoxins B1, B2, G1, G2 and ochratoxin A) in tobacco products. A tobacco sample was spiked with commercially available internal standards (U-[13C17]-AFB1 and U-[13C20]-OTA), and then extracted with methanol:water solution. After appropriate dilution with a phosphate buffered saline (PBS), sample clean up was achieved using an immunoaffinity cartridge. Three mass transitions for each analyte were evaluated to enhance the selectivity and accuracy of the method. The method exhibits good linearity (R2 = 0.999) over a concentration range of 0.05 to 50ng/mL for all the analytes. Kentucky reference KY 3R4F cigarette filler and CORESTA reference products for smokeless tobacco CRP-2, CRP-3 and CRP4 were tested during validation, no aflatoxins were detected in these samples, but low contents of ochratoxin A were found. Method accuracy and precision was assessed using laboratory fortified matrix samples at three concentration levels with recoveries ranging from 83.4 to 116% across all analytes tested. A simple direct LC-MS/MS method was also validated for fast Aflatoxin B1 analysis and screening without sample clean up, using 3R4F, CRP2, CRP3 and CRP4 reference samples as examples for its applications.