Determination of Ractopamine and Clenbuterol in Beef by Graphene Oxide Hollow Fiber Solid-Phase Microextraction and High-Performance Liquid Chromatography

A novel solid-phase microextraction method is reported that involved modification of the pores of hollow fibers with graphene oxide. The modified graphene oxide/hollow fiber was characterized by scanning electron microscopy and Raman spectroscopy and employed for the determination of ractopamine and clenbuterol in fortified beef. The repeatability of the method was satisfactory with intra-day and inter-day relative standard deviations between 2.5 and 5.2% for ractopamine and clenbuterol. Under the optimized conditions, the linear dynamic ranges of ractopamine and clenbuterol were from 0.05 to 2.5 µg/mL and 0.1 to 2.5 µg/mL, respectively. The limits of detection for ractopamine and clenbuterol were 0.01 and 0.03 µg/mL, and the limits of quantification were 0.03 and 0.08 µg/mL. The developed method was used for the determination of ractopamine and clenbuterol in fortified beef with average recoveries of 85.8–109.8% and 78.8–101.4%.