Determination of p-Nitroaniline in Water by Single-Layer Tungsten Disulfide-Carboxylated Multi-Walled Carbon Nanotubes Modified Glassy Carbon Electrode

Single-layer tungsten disulfide (WS₂) and carboxylate multi-walled carbon nanotubes (CMWCNTs) composites were prepared to modify glassy carbon electrode (GCE). The WS₂/CMWCNTs/GCE electrochemical sensor was constructed for the determination of p-nitroaniline (PNA) in water. The modified electrode was characterized by cyclic voltammetry (CV), and the electrochemical behavior of PNA on cyclic voltammetry was discussed. The results showed that the WS₂/CMWCNTs composite membrane had significant electro-catalysis for PNA. Cyclic voltammetry curve showed that in the pH 7.0 phosphate buffer solution, significant reduction peak of PNA was found at -0.7 V. After the conditions were optimized, linearity relationship between the concentration of PNA and its peak current value was ranged within 500 μmol·L^-1, with detection limit (3s/k) of 0.63 μmol·L^-1. The modified electrode was used to determine the sample of wastewater, recovery with adding standard was kept in the range of 92.8%-102%, and RSDs (n=6) of the measured values were found less than 5.0%.