Graphite Screen Printed Electrodes Functionalized with AuNPs-PEI for Nitrite Detection

This paper aims to develop a novel electrochemical sensor for nitrite (NO 2 −) detection as it is harmful to public health and environment beyond safe limits. The electrochemical sensor is based on graphite screen printed electrodes (GSPE) modified with non-toxic and biocompatible gold nanoparticles stabilized by branched polyethyleneimine (AuNPs-PEI). The functionalization of GSPE was carried out by drop casting of AuNPs-PEI solution, with the concentration of $300 \mu \mathrm{g}/\mathrm{mL}$ , onto GSPE and its electrochemical behavior in the presence of NO 2 − was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). After optimization of the operation conditions (pH and scan rate), the sensor provided the following figures of merit: linear range $1-10\ \mu \mathrm{M}$ ; sensitivity $0.8\ \mu \mathrm{A}/\mu \mathrm{M}$ , and limit of detection $1\ \mu \mathrm{M}$ . The results show that AuNPs-PEI/GSPEs are very promising for effective NO 2 − detection.