Reduced graphene oxide/ZnO nanocomposite modified electrode for the detection of tetracycline

摘要

In this work, rGO-ZnO (reduced graphene oxide-zinc oxide) nanocomposite was prepared and used for modification of GC (glassy carbon) surface in order to obtain an electrochemical sensor for tetracycline determination in water and urine samples by voltammetric technique. The characterization of synthesized nanocomposite was accomplished by utilizing SEM, EDS, AFM and FTIR analyses. The electrochemical behaviour of tetracycline on the modified GCE was studied by cyclic voltammetry and results revealed that modification enhanced the electro-oxidation of tetracycline with increased current intensity. Tetracycline provided a well-defined oxidation peak at around + 1.05 V vs. Ag/AgCl (3.5 mol/L KCl) in Britton-Robinson buffer (BRB) at pH 8.0. Then, square-wave voltammetry (SWV) was applied for analytical purposes. The influence of the supporting electrolyte (type, concentration and pH) and SWV parameters on the peak current was investigated in order to optimize the experimental and instrumental conditions for quantitative analysis. Under the optimal conditions, the prepared sensor exhibits a wide linear range (4-400 mu mol/L) with a low limit of detection (0.38 mu mol/L) and good reproducibility of analysis (RSD < 3.40%). In addition, the sensor showed high selectivity towards tetracycline analysis in comparison to interferences often present in real samples. The practical analytical usefulness of the presented sensing platform was successfully demonstrated in the determination of tetracycline in water and human urine with good recoveries.