Flow-Injection Amperometric Detection of Bisphenol F Using a Hierarchical Multimodal Nanoporous Gold-Multi-Walled Carbon Nanotube Modified Screen-Printed Electrode

In this paper, we report a flow injection electrochemical sensor for bisphenol F based on a hierarchical multimodal nanoporous gold (hm-NPG)/multi-walled carbon nanotube (MWCNT) nanocomposite deposited onto a screen-printed carbon electrode (SPCE). The hierarchical pore structure of hm-NPG provides an enhanced electroactive surface area arising from the smaller mesopores and efficient mass transport pathways due to larger macropores, while MWCNTs enhance electrical conductivity and electron transfer. Integration of the sensor with flow injection analysis (FIA) substantially reduced the loss of electrode response associated with electrode fouling arising from the electropolymerization of BPF during oxidation. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were employed to characterize the electrochemical behavior of the modified electrode, and chronoamperometry was used for quantitative detection. Under optimized conditions, the sensor exhibited a calculated limit of detection of 6.00 nM, with two linear concentration ranges of 0.5–10 μM and 10–100 μM. The sensor also demonstrated good repeatability (RSD = 5.64%), reproducibility (RSD = 5.78%), and limited response to some common environmental and commercial interferents. Application to spiked tap and bottled water samples demonstrated the potential of the hm-NPG/MWCNT-modified SPCE for BPF detection. The combination of hierarchical porosity of hm-NPG, MWCNTs, and FIA provides an effective strategy to improve the electrochemical detection of BPF while minimizing signal loss due to electrode fouling.