Determination of Oxytetracycline in Food Using a Disposable Montmorillonite and Acetylene Black Modified Microelectrode

Oxytetracycline is a broad-spectrum antibiotic used in animal husbandry that may cause the occurrence of antibiotic residues in food-producing animals. A detailed study of the electrochemical properties of oxytetracycline was carried out at montmorillonite and acetylene black modified carbon paste microelectrode. The oxytetracycline underwent an irreversible oxidation at montmorillonite-acetylene black/carbon paste microelectrode, which was an adsorption-controlled process with one proton and one electron. Using differential normal pulse voltammetry with accumulation at a fixed potential of 0.3V for 120s, oxytetracycline yielded a well-defined voltammetric response at 0.6V in pH 7.4 citric acid-Na2HPO4 buffer. Furthermore, the oxidation peak current of oxytetracycline at the montmorillonite-acetylene black/carbon paste microelectrode linearly increased with concentration in the range of 0.5-50 mu M with a low detection limit of 87nM (S/N=3). This methodology was successfully applied to the determination of oxytetracycline from food samples, suggesting that it has practical applications in monitoring oxytetracycline.