Development of an LC-MS/MS method for the determination of aflatoxins B1, B2, G1, and G2in Brazil nut

An LC-MS/MS method with atmospheric pressure chemical ionization in the positive mode [M + H]+, for simultaneous determination of the aflatoxins (AFLs): AFB1, AFB2, AFG1 and AFG2 in Brazil nuts matrix is described. By means of multiple reaction monitoring it was possible to analyse the AFLs fragment ions to increase specificity and sensitivity. The separation of the toxins was carried out in a C8 column with gradient mobile phase composed of water:methanol (25 mM ammonium acetate) in a total run time of 5.0 min. The toxin extraction solvent was acetonitrile : water (80 : 20) and no clean up was required for the Brazil nut samples. The method values of LOD and LOQ utilizing the Brazil nut matrix for AFB1, AFB2, AFG1 and AFG2 were 0.04; 0.045; 0.050 and 0.060 µg kg−1; 0.08, 0.09, 0.10 and 0.12 µg kg−1, respectively. The recoveries from the Brazil nuts were between 92 and 100% and ΣAFL levels obtained from the positive naturally contaminated Brazil nuts ranged from 1.2 to 11.5 µg kg−1.