Tris(1,10-phenanthroline)iron(II)-bentonite film as efficient electrochemical sensing platform for nitrite determination

• Tris(1,10-phenanthroline)iron(II)-bentonite film is used for nitrite detection.
• Kinetic and analytical parameters for nitrite oxidation are evaluated.
• Influence of common interferences is negligible.
• The sensor exhibits high stability, selectivity and sensitivity for nitrite.

Development of an efficient amperometric sensor for nitrites using Fe(phen)32+ (where phen = 1,10-phenanthroline) incorporated a bentonite film as electrochemical sensing platform (ESP) is reported. The ESP showed high electrocatalytic activity for nitrite oxidation by decreasing the nitrite oxidation potential and increasing the peak current. It shows linear increase in current with increase in the concentration of nitrite from 1.0 μM to 100.0 mM and 1.0 μM to 25.0 mM by cyclic voltammetry and amperometry, respectively. Kinetic parameters such as catalytic rate constant, diffusion coefficient, etc. are evaluated using chronoamperometry and chronocoulometry. Magnitude of interference caused by other species has been examined in simulated mixtures containing high concentration of interfering species and the influence of interferences was found to be negligible. The constructed sensor is successfully applied for the determination of nitrite in potable water samples.