Development of Pen-type Portable Electrochemical Sensor Based on Au-W Bimetallic Nanoparticles Decorated Graphene-chitosan Nanocomposite Film for the Detection of Nitrite in Water, Milk and Fruit Juices

The development and fabrication of a simple, portable, and sensitive detection tool to precisely monitor nitrite level is of growing importance in electrochemistry research, given the strong interest in the protection of drinking water quality, treatment of wastewater, food production, and control of remediation processes. This work describes the fabrication of a simple, cost-effective, pen-type electrochemical sensor based on bimetallic gold and tungsten nanoparticles electrochemically decorated on graphene-chitosan modified pencil graphite electrode (PGE) for the trace detection of nitrite in real samples. The prepared nanocomposite was characterized using XRD, SEM, and EDS. The electrochemical behavior of the sensor was evaluated by cyclic voltammetry (CV) and impedance electrochemical spectroscopy (EIS). Results revealed that the proposed sensor displayed excellent electrocatalytic activity towards electro-oxidation of nitrite with an irreversible redox reaction. The AuNPs-WNPs@Gr-Chi/PGE sensor exhibited excellent analytical performance with a wide linear range from 10 to 250 mu M towards nitrite. The LOD and LOQ were calculated to be 0.12 mu M and 0.44 mu M, respectively. The designed electrochemical sensor was successfully applied for the detection of nitrite in water, milk, and natural fruit juice samples.

Automated summary

This study involves the development of a simple and cost-effective pen-type electrochemical sensor for trace detection of nitrite in real samples by electrochemically decorating bimetallic gold and tungsten nanoparticles on graphene-chitosan modified pencil graphite electrode. The sensor exhibited excellent electrocatalytic activity and analytical performance towards nitrite, with a wide linear range and low detection limits. It was successfully applied for nitrite detection in water, milk, and natural fruit juice samples.