Chitosan-stabilized silver nanoparticles for voltammetric detection of nitrocompounds

A material comprised of chitosan-stabilized silver nanoparticles (nAg-chitosan) was prepared and characterized by UV–vis and TEM. The average diameter of the nAg obtained was 3.4 nm and the particles were well dispersed in the chitosan matrix. The liquid suspension of nAg-chitosan was deposited by the drop-coating method onto a glassy carbon electrode (GCE) surface to build a voltammetric sensor (nAg-chitosan/GCE sensor). The voltammetric sensor was successfully used for the detection of nitrocompounds. Under optimized experimental conditions, a reduction peak current was observed which increased with increasing concentrations of 4-nitrophenol (4-NP) in the range of 0.07 to 2.0 μmol L−1 (R2 = 0.994). The visual detection limit was 70 nmol L−1. At this level of concentration, the sensor was not sensitive to other nitrophenols. For concentrations higher than 0.05 mmol L−1 the sensor was sensitive to the three isomers, namely 2-NP, 3-NP and 4-NP. These findings indicate that the material comprised of chitosan-stabilized silver nanoparticles is a very promising candidate to assemble voltammetric sensors for practical applications in the field of analytical chemistry.