Electroanalytical application of Ag@POM@rGO nanocomposite and ionic liquid modified carbon paste electrode for the quantification of ciprofloxacin antibiotic

Abstract

In this work, introduction of a sensitive electrochemical nanosensor based on carbon paste electrode (CPE) modified by silver decorated in polyoxometalate (POM), reduced graphene oxide (rGO) and ionic liquid (IL) was developed for measurement of ciprofloxacin (CIP). For this purpose, Ag@POM@rGO nanocomposite was firstly prepared and identified by various methods. The peaks of C 1 s, O 1 s, P 2p, Ag 3d and W 4f in the XPS spectra confirmed formation of the Ag@POM@rGO. The effects of Ag@POM@rGO and IL amounts, pH and scan rate were examined on the response of CIP electro-oxidation by Design-Expert software. Based on the obtained results, the modified electrode with 0.01 g of IL and 0.04 g of Ag@POM@rGO in phosphate buffer solution (0.1 M, pH 7.0) with at a scan rate of 0.07 V s−1 displayed the best electrochemical response. The oxidation overvoltage of CIP was significantly reduced compared to CPE and its oxidation current was increased dramatically. In the optimum situation, the calibration curve for CIP was obtained by SWV technique and limit of detection (LOD) and linear dynamic ranges (LDR) were attained to be 0.031 µM and 0.103–122.880 µM, respectively. The electron-transfer coefficient, catalytic rate constant and diffusion coefficient were obtained to be 0.855, 3.91 × 106 cm3 mol−1 s−1 and 2.52 × 10−5 cm2 s−1, respectively. Also, the practical application of Ag@POM@rGO-IL/CPE was considered by determining the concentration of spiked CIP in human plasma with good recovery. The planned procedure is easy, fast and inexpensive and might be used as an important analytical implement in quality control of the pharmaceutical industry.