The determination of tetracycline residues in food using a disposable screen-printed gold electrode (SPGE)

The electrochemical analysis of tetracyclines was investigated using a gold screen-printed electrode by cyclic voltammetry and flow injection analysis with dc amperometry. Cyclic voltammetry was used to study the electrochemical oxidation of tetracyclines. For all the tetracyclines investigated a well-defined cyclic voltammogram providing the highest peak current, at 1.2 V versus Ag/AgCl, was obtained when using potassium dihydrogen phosphate solution at pH 2. Flow injection analysis with dc amperometry using the specially fabricated wall-jet flow-through cell was also studied. Under amperometric conditions (Eapp = 1.2 V; flow rate = 2.0 mL min−1), analytical calibration graphs for tetracycline, chlortetracycline and oxytetracycline were obtained from 1 to 500, 5 to 50 and 1 to 500 μmol L−1 with detection limits of 0.96, 0.58 and 0.35 μmol L−1, respectively. The proposed method was successfully applied to the determination of tetracycline, chlortetracycline and oxytetracycline in pharmaceutical products and foods.