Multitoxin immunoaffinity analysis of aflatoxins and ochratoxin A in spices

A multitoxin method for aflatoxins (AFs) and ochratoxin A (OTA) was modified and validated to analyze black pepper, colorífico, nutmeg, paprika, and turmeric. The method consisted of acetonitrile, NaHCO3 and methanol extraction solution, multimycotoxin immunoaffinity column purification and isolation, reversed‐phase liquid chromatography separation, and fluorescence detection. The limit of detection was <0.1 ng/g for AFs and OTA. Mean recoveries of added AFs ranged from 68 to 88% with relative standard deviation of repeatability (RSDr) values <15%; aflatoxin B1 (AFB1) from 69 to 92% with RSDr <17%; and OTA from 75 to 110% with RSDr <10% at spiked levels ranged from 8 to 40 ng/g for AFs, 4 to 20 ng/g for AFB1, and 4 to 20 ng/g for OTA, respectively. Recoveries of added aflatoxin G2 were approximately 50% at spiked levels ranged from 1 to 5 ng/g. Recoveries of aflatoxin B2 and aflatoxin G1 were >70%. The linearity of the method for AFs ranged from 0.4 to 100 ng/g, for OTA from 0.2 to 40 ng/g with R2 values exceeding 0.99. Results of a single laboratory validation study validated the performance of this method meeting the method acceptability criteria. No differences in toxin detection were determined in robustness testing in which minor changes were introduced to the method.