Detection of trace nitroaromatic isomers using indium tin oxide electrodes modified using β-cyclodextrin and silver nanoparticles.

The determination of nitroaromatic compounds in aqueous solution was investigated at β-cyclodextrin (β-CD)/silver nanoparticle (AgNPs) composite modified ITO electrodes. This method relies on the different reduction potentials for the various nitroaromatic isomers, the different binding strengths of the nitroaromatic isomer guests to the β-CD host, and excellent electron transfer ability of AgNPs. After incubation in a solution with different single nitroaromatic compounds, reduction peaks in the range from -550 to -913 mV were observed at the modified electrode, depending on the nitroaromatic compound present. The sensor exhibited selectivity for some isomers in a solution containing a mixture of nitroaromatic compounds. In particular, the sensor shows specificity for 4-nitroaniline and 1-chloro-2-nitrobenzene over other nitroaniline isomers and nitrochlorobenzene isomers, respectively. The results show that all the nitroaromatic compounds, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 1-chloro-2-nitrobenzene, 1-chloro-3-nitrobenzene, and 1-chloro-4-nitrobenzene, could not only be detected but the electrode demonstrated a preference for the more strongly complexing species.