Sensitivitas Elektroda Termodifikasi Kitosan/Oksida Grafena Tereduksi dalam Mendeteksi Konsentrasi Pupuk Urea Menggunakan Voltametri Siklik

Abstract

Chitosan (CS)/reduced graphene oxide (rGO) modified platinum electrode has been successfully tested using cyclic voltammetry (CV) method to detect urea fertilizer concentration. Chitosan-reduced graphene oxide (rGO) was fabricated using the drop casting method, in which the mixed solution was deposited onto the surface of the platinum substrate. Both solutions were prepared using a volume ratio of 1:1, where the mixed solution consisted of 1.5% chitosan solution and rGO solution with various concentrations of 200, 250, 300, 350, and 400 ppm. Furthermore, for the test sample solution of urea fertilizer, it was made with various concentrations, namely 50, 100, 150, 200, and 250 ppm. The chitosan-rGO films were characterized using Fourier Transform Infra-Red (FTIR) and X-Ray Diffraction (XRD) methods. Based on the results of FTIR and XRD analysis, it showed that rGO interacted physically with CS and has 22θ at 9.8°; 18.59°; 22.57°, dan 37,14° with d-spacing 9,9 Å. Based on the test results using the cyclic voltammetry (CV) method, the CS/rGO electrode had optimum results at a concentration of 250 ppm rGO in a PBS pH 7 electrolyte solution and optimum detection of 150 ppm urea fertilizer with a potential value of - 0.29626 V. The optimum results chitosan-rGO modified electrodes in detecting urea fertilizer was strengthened by the presence of good linearity at a regression value of 0.6933 and a limit of detection of 105 ppm. It indicates that chitosan-rGO modified electrodes has moderate sensitivity for the detection of urea fertilizer and can be applied as a sensor-based material, especially for detecting of fertilizer concentrations.