Extraction of tetracycline in food samples using biochar microspheres prepared by a Pickering emulsion method.

We report for the first time the use of biochar as a stabilizer for oil-in-water (o/w) Pickering emulsion. The emulsion is subsequently used to prepare tetracycline-imprinted biochar composite microspheres (MIPMs) with tailored sizes and good uniformity. The adsorption properties of tetracycline to the MIPMs were investigated using different adsorption experiments including adsorption kinetic experiment, equilibrium binding experiment, selectivity evaluation and competitive adsorption tests. The MIPMs were used as adsorbent for solid phase extraction (SPE) for the extraction of tetracycline present in drinking water, fish, and chicken samples. Under optimal conditions, the results showed good recovery yield ranging from ~73% to ~95% with a relative standard deviation (RSD) ranging from ~0.3% to ~8.4%, respectively.