Interaction of Mycotoxins with Copper-Folin Reagent

To study the interference by mycotoxins in protein measurements, solutions of various concentrations of aflatoxin B₁, citrinin, cytochalasin B, ochratoxin A, patulin, penicillic acid, rubratoxins A and B, T-2 toxin and zearalenone were tested for a positive copper-Folin reaction. Except for T-2 toxin, all mycotoxins tested developed a blue color, characteristic of proteins, in the copper-Folin solution. The Lowry reaction for the mycotoxins was linear over the concentration range of 20-100 μg/ml for most of these toxins. Aflatoxin B₁ and citrinin at 2 μg/ml and zearalenone at 0.5 mg/ml developed a blue color in the copper-Folin solution. The linear relationship between color development and toxin concentration plus high sensitivity makes the copper-Folin reaction a potential analytical method for these toxins but only in the absence of protein or other copper-Folin positive materials.