A Rapid Enzymatic Method for Aflatoxin B Detection

A novel method for aflatoxin B (AFB) determination is proposed. The AFB determination is based on acetylcholinesterase (AChE, from electric eel ) inhibition, and the AChE residual activity is determined using the colorimetric method (Ellman’s method). To select and optimize the analytical procedures, the investigation on type of AChE inhibition by AFB₁ was carried out. The AChE degree of inhibition by AFB₁ was independent of the incubation time and the enzyme concentrations, showing the reversibility of the inhibition. This reversibility of the inhibition permits a rapid analysis of AFB₁ . In fact, only a 3-min analysis is required. For the development of AFB₁ assay, the pH, the reaction time, the temperature, and the substrate concentration were evaluated and optimized. The linear range of 10–60 ng/mL was assessed. To evaluate the selectivity of this method, the cross-reactivity with other aflatoxins, such as AFB₂ (aflatoxin B₂ ), AFG₁ (aflatoxin G₁ ), AFG₂ (aflatoxin G₂ ), and AFM₁ (aflatoxin M₁ ), was investigated. The suitability of the assay for AFB₁ quantification in barley was also evaluated. This study shows a new approach to detect aflatoxins based on enzyme inhibition with several advantages, such as the easiness of use, the rapidity, and the cost-effectiveness, demonstrating a possible use as screening method for this type of mycotoxins.