Voltammetric determination of oxytetracycline in milk and pharmaceuticals samples using polyurea modified glassy carbon electrode

Abstract

Oxytetracycline (OTC) is one of the most commonly utilized broad spectrum antibiotic for the therapy of humans and animals. The present work describes the establishment of a simple, new and sensitive sensor based on elelctropolymerized polyurea modified glassy carbon electrode (EPPU/GCE) for OTC determination, which is one of the most frequently used antibiotics to treat certain diseases. Though urea is a simple, inexpensive and nontoxic, its use in the development of modified electrodes for electrochemical determination of pharmaceuticals has not been studied. The fabricated sensor (EPPU/GCE) was characterized via cyclic voltammetry and electrochemical impedance spectroscopy using Fe(CN)63-/4- solution as a probe. The electrochemical activity of poly(EPPU)/GCE for oxytetracycline oxidation was examined with phosphate buffer solution (PBS) of pH 7.5. A well-resolved and more enhanced two oxidative peaks for OTC solution in phosphate buffer solution (PBS) of pH 7.5 were observed at EPPU/GCE. The SWV measurement demonstrated a good linear range (1–200 µM) and detection limit (Ipa1 =1.01 ×10−1 µM and Ipa2 = 9.83 ×10−2 µM) for OTC. Electrochemical response of OTC at EPPU/GCE was not influenced by the presence of paracetamol, uric acid and glucose, showing good selectivity. The fabricated sensor has been effectively applied for detecting OTC in milk and four brands of veterinary injection samples, and the detected percentage recovery of OTC in each injection sample was above 99.25% of the labeled value and above 96% for milk sample. Thus, the developed sensor could potentially be used for electrochemical determination of OTC in other pharmaceuticals, biological, environmental and food samples.