Paper-based sensor with electro-modified chitosan/silver nanoparticles for rapid and sensitive nitrite detection

Abstract

The presence of high concentration of nitrite in natural environment and food can be harmful to water ecosystems and human health. It is of great significance to develop a reliable detection method for nitrite. In this work, a modified paper sensor (CS/AgNPs-PE) was fabricated by electrodepositing chitosan (CS) and electrochemically reducing silver nanoparticles (AgNPs) onto an oxidized graphene/cellulose/carbon fiber composite paper sensor. The successful loading of chitosan and AgNPs enhances the electrocatalytic activity of the sensor, improving the detection performance of nitrite. The electrochemical process of nitrite on the surface of the CS/AgNPs-PE was proven to be a diffusion-controlled irreversible reaction. Cyclic voltammetry and differential pulse voltammetry (DPV) were used to quantitatively analyze nitrite. A low detection limit of 7.9 × 10−7 mol L−1 can be obtained by DPV under a wide nitrite detection range of 4.0–1000 µM. CS/AgNPs-PE sensor exhibited good repeatability and selectivity, and it could be used to detect nitrite in tap water and ham samples. These results suggest that the CS/AgNPs-PE sensor is of great potential for nitrite sensing in real samples.