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 nitro-compounds. 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 mu mol L-1 (R-2=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. (C) 2014 Elsevier B.V. All rights reserved.