Electrochemical Detection of Zeranol and Zearalenone Metabolic Analogs in Meats and Grains by Screen-Plated Carbon-Plated Disposable Electrodes

Zeranol (Z) is an estrogenic growth-promoting agent synthesized from mycotoxin zearalenone (Zen). Inadvertent consumption of Z and its structural analogs from meat or grain products remain a food safety concern. An economic and rapid high performance liquid chromatography method with electrochemical detection using disposable screen-printed carbon electrode is developed for determination of Z, Zen and 3 major metabolic analogs α-zearalenol (α-Ze), β-zearalenol (β-Ze), and β-zearalanol (β-Za). The electrochemical method was validated for application in food matrices including beef, pork, feed and cereal after optimized liquid and/or solid-phase extraction procedures. All 5 Z analogs were separated in 10 minutes with the limits of detection ranging from 15 ng/ml for α-Ze and 25 ng/ml for Z and Zen; the limit of quantitation ranged from 40 50 ng/ml. The recoveries were all above 75% regardless of matrix types and extraction procedures. The intra and inter day variations were both less than 6% at the nominal concentration of 1 μg/ml and less than 13% at 100 ng/ml level. Chromatographically time-matched peaks of Z, α-Ze and β-Za were observed in moldy feed, cereal and rice with high productivity, indicating possible grain-specific Zs exposure for animals and human. Proper exercise of preservative procedures for grain and grain products to prevent it from mold production is imperative. The simplicity and reproducibility of this method affords quick and reliable quantitation of multiple types of Z analogs in food products and can offer semi-confirmative information comparable to UV detection and supplementary to ELISA screening.