Direct electrochemical sensing for oxytetracycline in food using a zinc cation-exchanged montmorillonite

Direct voltammetric determination of oxytetracycline (OTC) at a zinc cation-exchanged montmorillonite modified glassy carbon electrode (Zn-Mt/GCE) was described. The OTC yielded one well-defined oxidation peak at the Zn-Mt/GCE. The experimental parameters, which influence the voltammetric responses of OTC, e.g., the pH value, scan rate and accumulation condition, were optimized. The oxidation peak current changed with the OTC concentration over the range from 0.80 to 40 μM. The detection limit was 0.12 μM for an accumulation time of 4 min. The coefficient of variation, determined at 10 μM OTC, was 3.4% (n = 10). Using this method, OTC in the real food and feedstuff samples was determined.