Determination of tetracycline residue in pork by differential pulse voltammetry using activated glassy carbon electrode

Abstract

A simple and environment friendly electrochemical method using activated glassy carbon electrodes (aGCE) for monitoring the residues of tetracycline in pork samples was developed. A two step pretreatment procedure was established for activating the glassy carbon electrode surface, including mechanical polishing and electrochemical pretreatment. In the supporting electrolyte solution of 0.2 M sodium sulfate (at pH 2.5), the electrochemical response of TC was characterized by two irreversible oxidation peaks at +0.95 V and +1.05 V vs. saturated calomel electrode. The differential pulse voltammetry (DPV) current density response of aGCE for TC exhibited two distinct linear response ranges of 2.0×10⁻⁶+1.6×10⁻⁵ M and 1.6×10⁻⁵÷8.3×10⁻⁵ M. The limit of detection and the limit of quantitative was 0.23×10⁻⁶ M and 0.77×10⁻⁶ M, respectively. Liquid liquid extraction has been applied for the determination of TC residues in pork samples sold in the market of Ho Chi Minh City, Vietnam, with the percentage recoveries of TC varying from 80.1% to 88.0% (n=5). The obtained results of the introduced electrochemical method were in good agreement with the results of high performance liquid chromatography mass spectrometry (HPLC-MS/MS).