A new disposable electrochemical sensor for the individual and simultaneous determination of carbamate pesticides using a nanocomposite modified screen-printed electrode

Abstract

In this work, we developed a disposable electrochemical sensor with improved sensitivity for the individual and simultaneous detection of carbaryl (CBR), fenobucarb (FNB), and carbosulfan (CBS) pesticides. The device used a screen-printed carbon electrode (SPCE) modified with a nanocomposite comprising manganese dioxide nanoparticles (MnO2) and graphene nanoplatelets (GNPs). We prepared the MnO2-GNPs nanocomposite by an in-situ growth method. The product was characterized by X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The disposable sensor was fabricated by inhouse-printing using only carbon ink on inexpensive transparency paper. We investigated the electrochemical performance of the developed sensor by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The MnO2 and GNPs nanocomposite shows the highest electrocatalytic activity toward the oxidation of carbamate when in its phenol form. Under the optimized experimental conditions, the proposed strategy possess a good linear response of the disposable sensor for the individual determination of CBR, FNB and CBS in the concentration range of 1-40 μM, 5-150 μM and 50-600 μM with the low detection limit of 0.30 μM, 1.30 μM, 14.90 μM, respectively. Besides, the analytical performance of the proposed sensor for the simultaneous detection of CBR, FNB, and CBS exhibits a linear response in ranges of 1–30 µM, 5–80 µM, and 50–400 µM, with the limit of detection being 0.30, 1.40, and 15.15 µM, respectively. In addition, the sensor displays high reproducibility, repeatability, and good selectivity. The electrode simultaneously applied to determine the three carbamate residues in Jasmine rice and rice-field water samples. This developed electrochemical sensor is a promising high-sensitivity tool for fast, easy-to-use, low-cost electrochemical detection of multi-pesticide residues in agricultural samples.