Electrode modified with CO2 laser-reduced graphene oxide-silver nanoparticles for determination of nitrite in water

Abstract

Intercalation of rGO with AgNPs was achieved photothermally through CO2-assisted laser irradiation of GO and Ag+ precursors in the solid state. A uniform distribution of AgNPs was anchored on rGO (LrGO-AgNPs). The LrGO-AgNPs nanocomposite was structurally and electrochemically characterized. The parameters for the fabrication of LrGO-AgNPs and electrochemical NO2− detection were optimized. Under optimal conditions, the glassy carbon electrode (GCE) modified with LrGO-AgNPs showed a high diffusion coefficient and electron transfer rate constant for NO2− oxidation. Aditionally, the modified electrode displayed outstanding electrocatalytic activity toward NO2− oxidation with a sensitivity of 114.6 μA μM−1 cm−2 and an estimated response time of 7 s. The linear concentration range, LOD, and LOQ were 0.1–10,000, 0.039, and 0.131 μM, respectively. The proposed amperometric sensor was applied to detect carcinogenic nitrite in water samples and obtained recoveries between 93 ± 3 % and 103.3 ± 0.3 %. The results of the proposed method and the UV–vis spectrophotometric method showed no significant differences, indicating the potential of the proposed sensor for wider applications.