Development of a paper-based, inexpensive, and disposable electrochemical sensing platform for nitrite detection

Electrochemical techniques are attractive for nitrite detection owing to their intrinsic advantages. However, traditional electrochemical sensors often suffer from the effects of fouling due to the adsorption of oxidation products on the electrode surface. In this work, a paper-based, inexpensive, disposable electrochemical sensing platform was developed for nitrite analysis based on a simple and efficient vacuum filtration system. Taking advantage of the physicochemical properties of graphene nanosheets and gold nanoparticles, the mass transport regime of nitrite at the paper-based electrode was thin layer diffusion rather than planar diffusion. In comparison with the electrochemical responses of commercial gold electrodes and glassy carbon electrodes (GCE), a considerably larger current signal was seen at the paper-based sensing interface, which significantly improved its sensitivity for nitrite detection. In particular, the paper-based electrode was a disposable sensing device, so that it effectively avoided the fouling effect arising from the adsorption of oxidation products. Moreover, the paper-based sensing platform made it possible to determine nitrite in environmental and food samples in an accurate, convenient, inexpensive, and reproducible way, indicating that the proposed system is promising for practical applications in environmental monitoring and public health.