Electropolymerization of Indole-3-acetic Acid on Glassy Carbon Electrode for Sensitive Detection of Nitrite

Highly uniform and adhesive films of poly(indole-3-acetic acid) (p-IAA) were fabricated on the glassy carbon electrode (GCE) by electropolymerization of indole-3-acetic acid (IAA). The p-IAA modified GCE (p-IAA/GCE) was constructed to develop a promising amperometric sensor for the sensitive determination of nitrite. Field emission scanning electron microscope (SEM) and electrochemical techniques were used for the surface characterization of the modified electrode. It was demonstrated that p-IAA modified GCE (p-IAA/GCE) exhibited remarkable electrocatalytic activity towards the oxidation of nitrite with obvious reduction of overpotential. Under the optimal conditions, the linear range for the detection of nitrite was 5.0×10-7 to 5.0×10-4 M with a high sensitivity of 0.105 AM-1, and a low detection limit of 1.0×10-7 M (S/N = 3). The influence of various anions and cations on the nitrite detection has been studied. The proposed method was successfully applied in the detection of nitrite in sausage samples, and the results were consistent with those obtained by UV-vis spectrophotometric methods.