Activated jute carbon paste screen-printed FTO electrodes for nonenzymatic amperometric determination of nitrite

Aiming at constructing a new nonenzymatic electrochemical nitrite sensor, we have prepared a screen-printed fluorine-doped tin oxide (FTO) electrode with activated jute carbon paste (AJCP) (AJCP-SP-FTO) synthesized from jute (Corchorus genus) sticks by using ZnCl₂ as activating agent and subsequent carbonizing at 850 °C. Surface morphology, textural properties, chemical composition and nature of pores of AJC were studied by FE-SEM, XRD, EDS, Raman spectroscopy and BET analysis. The surface area of the AJC was found to be 1452.4 m²/g with an average pore diameter of 2.6 nm obtained from a BJH pore-size distribution curve. Electron transfer capacity at the interface of the AJCP material screen-printed FTO was studied by cyclic voltammetry (CV) and EIS techniques. The AJCP-SP-FTO sensor was used for amperometric detection of nitrite. The limit of detection (LOD) for nitrite oxidation was found to be 437 nM for the proposed sensor. The sensitivity of AJCP-SP-FTO toward nitrite was 863.71 μA mM⁻¹ cm⁻². From the analysis of electrochemical data, the effective surface area of the AJCP-SP-FTO was 0.12 cm². We proposed a mechanism for sensitive detection of nitrite based on analysis of experimental findings of spectroscopic and electroanalytical techniques. We further utilized the proposed sensor for analyzing nitrite in tap water. The AJCP-SP-FTO electrode showed good reproducibility and stability.