Simple, rapid, and inexpensive cleanup method for quantitation of aflatoxins in important agricultural products by HPLC

Authors: Sobolev, Victor

Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2007
Publication Date: 2/24/2007
Citation: Sobolev, V.S. 2007. Simple, rapid, and inexpensive cleanup method for quantitation of aflatoxins in important agricultural products by HPLC. Journal of Agriculture and Food Chemistry. 55(6):2136-2141.

Interpretive Summary: Agricultural commodities are often infected by microscopic fungi Aspergillus flavus and A. parasiticus and, as the result, become contaminated with the carcinogenic aflatoxins. Legislators of most developed nations regulate limits of aflatoxins as low as reasonably achievable (2 µg/kg for aflatoxin B1 in the European Union). Such low limits require adequate cleanup procedures, the backbone of practical methods of detection and quantitation of aflatoxins in agricultural products and food. Such a procedure has been developed. The procedure uses selective adsorption of aflatoxins on Florisil, a cheap commercial adsorbent, from agricultutal commodities extracted by common non-toxic solvents. Use of Florisil allowed developing a simple, fast, highly sensitive, and cheap chemical method for quantitative determination of aflatoxins in major important agricultural commodities. The minimal cost of the Florisil minicolumn allows for substantial savings compared with available commercial aflatoxin cleanup devices.

Technical Abstract: A simple, fast and cheap chemical cleanup procedure for low-level quantitative determination of aflatoxins in major economically important agricultural commodities using HPLC has been developed. Aflatoxins were extracted from a ground sample with methanol-water (80:20, v/v), and after a cleanup step on a minicolumn packed with Florisil, aflatoxins were quantified by HPLC equipped with a C18 column, a photochemical reactor, and a fluorescence detector. Water - methanol (63:37, v/v) served as the mobile phase. Recoveries of aflatoxins B1, B2, G1, and G2 from peanuts spiked at 5, 1.7, 5, 1.7 mg/kg, respectively, were 89.5 ± 2.2, 94.7 ± 2.5, 90.4 ± 1.0, 98.2 ± 1.1. Similar recoveries, precision, and accuracy were achieved for corn, brown and white rice, cottonseed, almonds, Brazil nuts, pistachios, walnuts, and hazelnuts. The quantitation limit in peanuts was 50 pg/g for aflatoxin B1, and 17 pg/g for aflatoxin B2. The minimal cost of the minicolumn allows for substantial savings compared with available commercial aflatoxin cleanup devices.