Homopolymerization of 3-aminobenzoic acid for enzyme-free electrocatalytic assay of nitrite ions

We present a method for non-enzymatic detection of the nitrite ion (an inherent carcinogen) using poly-3-aminobenzoic acid (P-3ABA) synthesized by an electrochemical method. Its synthesis was confirmed using scanning electron microscopy and spectroscopy (X-ray powder diffraction, energy-dispersive X-ray, X-ray photoelectron, Fourier-transform infrared). P-3ABA electrocatalyzed oxidation of nitrite to nitrate using cyclic voltammetry and differential pulse voltammetry. The synthesized P-3ABA had a low limit of detection (LoD) (0.15 mu M, S/N = 3), high sensitivity (1.5 mu A mu M-1 cm(-2)), stable and highly reproducible responses with a relatively wide linear range (10-140 mu M). A P-3ABA-modified glassy carbon electrode displayed good applicability in determination of nitrite in real samples in various matrices. Therefore, we present P-3ABA as a novel, cost-effective and promising nitrite sensor for protection of human health.