First Two-Way Electrochemical Sensor for the Detection of the Pollutant 2,4-Dinitrophenylhydrazine and Its Metabolite Based on Cu-Containing Tungstophosphate and Graphene Oxide

Abstract

2,4-dinitrophenylhydrazine (2,4-DNPH) is a toxic organic pollutant which is highly threatening to human beings and their living environment. Therefore, it is of great significance to develop sensors for detecting 2,4-DNPH and its metabolites. To develop a two-way electrochemical sensor for the detection of 2,4-DNPH and its metabolite, Cu-containing tungstophosphate (Na16P4W30Cu4(H2O)2O112·nH2O, Cu4P4W30) was selected to study its electrocatalytic activity for the reduction of 2,4-DNPH and oxidation of its metabolite. First, the electrochemical behavior of Cu4P4W30 was investigated in solution; then, the films containing Cu4P4W30 and graphene oxide (GO) were fabricated on indium tin oxide (ITO) to form the modified ITO/PDDA/(Cu4P4W30/PDDA-GO)n electrode and the effect of the layer number on the electrocatalytic performance of the modified electrode was studied, confirming the optimal film layer number. Furthermore, the sensing performance of the modified electrode was tested, giving a linear concentration range and detection limit. Finally, the stability, repeatability, and reproducibility of the modified electrode were evaluated. The findings demonstrated that the proposed electrode acted as a two-way electrochemical sensor for the detection of 2,4-DNPH and its metabolite.