Highly Sensitive Determination of 4-Nitrophenol at a Nafion Modified Glass Carbon Nanofilm Electrode

Abstract

In this work, a highly sensitive electrochemical sensor for 4-nitrophenol (4-NP) was facilely constructed based on a Nafion modified glass carbon nanofilm electrode (Nafion-GCNFE). The GCNFE with high activity was quickly fabricated from a smooth GC surface in a blank electrolyte solution of H2SO4 with square wave potential pulses (SWPPs), where the nanofilm formation might be related to repeated anodic oxidation coupled with SO42− intercalation/deintercalation. Moreover, a Nafion modifier can improve the 4-NP adsorption on GCNFE, as confirmed by the Fourier transform infrared spectroscopy (FTIR), and hence increased the differential pulse voltammetry (DPV) response of 4-NP. The influence of pulse potential, pulse time, pulse frequency, and Nafion amount on the DPV signal of 4-NP was investigated in detail. Under an optimized detection condition, the electrochemical sensor based on Nafion-GCNFE exhibited excellent performances in sensing 4-NP with a wide linear range of 10 nM to 50 μM, a very low detection limit of 4 nM (3σ/slope), good reproducibility and reusability, high selectivity and long-term stability (over four weeks), which was successfully used for the 4-NP determination in real water samples with satisfied results.