Copper nanoparticles embedded chitosan for efficient detection and reduction of nitroaniline.

In this study, we proficiently designed metal nanoparticles embedded in chitosan biopolymeric matrices, which have the ability to be employed simultaneously for the recognition and complete reduction of 4-nitroaniline. Copper nanoparticles embedded chitosan (CuNPs-CH) were coated on glassy carbon electrode to design an efficient electrochemical sensor for 4-nitroaniline. The sensing ability of CuNPs-CH modified electrode toward 4-nitroaniline was assessed by cyclic voltammetry, amperometry and chronoamperometry at working potential of -0.76 V and pH 7.0, while the complete reduction of 4-nitroaniline was analyzed by UV-visible spectrophotometer. The sensing features of CuNPs-CH modified electrode include a sensitivity of -8.166 μA mM-1 cm-2, and detection limit of 0.37 μM. The catalytic ability of CuNPs-CH for 4-nitroaniline reduction reaction was investigated. The results displayed that 4-nitroaniline completely transformed to diaminobenzene in short contact time with a rate constant of 7.51 × 10-3 s-1. The reduction aptitude of CuNPs-CH was also examined toward 4-nitrophenol and rhodamine B; however, the designed system was more efficient toward 4-nitroaniline. The developed approach offered a new methodology for simultaneous detection and reduction of 4-nitroaniline simply for environmental safety purposes.