Preparation of tetracycline moleculary imprinting electrochemical sensor and rapid detection of tetracycline residues in milk and pork

A novel molecular imprinted electrochemical sensor was prepared by electro-polymerization on the surface of a glassy carbon electrode in phosphate buffer solution,and tetracycline was used as template moleculer,o-phenylenediamine( OPD) as functional monomer.The sensor could specifically recognize the template molecule and its analogues.In the experiment,the HAc-Na Ac buffer solution containing 1 mol/L KCL and 5 mmol/L K₃Fe( CN)_6was used as characterization solution,the electrochemical sensor response characteristics were researched,and the preparation and detection conditions of the sensor were optimized by differential pulse voltammetry( DPV) and cyclic voltammetry( CV).The results showed that the sensor had a good selectivity under the optimal conditions,the linear relationships between DPV peak current difference and the concentrations of tetracycline,oxytetracycline and doxycycline hyclate were found in the range of 0.002 ~ 0.02 mmol/L with the detection limits between 6.0 × 10^-7 and 7.5 × 10^-7mol/L. The sensor in methanol-H₂SO₄ solution was renewable,and had good reproduction,stability and good selectivity to tetracycline and its analogues. The tetracycline,oxytetracycline and doxycycline in real samples,such as milk and pork,were detected by the sensor,the average recoveries were between 82.8% and 97.4%,the relative standard deviations( RSD) were less than 4.43%. This sensor was simple,sensitive,low cost,and had a good stability,which provided it a good application prospect.