The use of cyclodextrin template-based metal oxide nanomaterials in the development of electrochemical sensors for phenolic endocrine disruptor compounds
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Iron oxide nanoparticles were prepared using co-precipitation method in the presence and absence of beta-cyclodextrin β-CD). Such materials were characterized using transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). The TEM shows that the surface morphology has no difference between nanoparticles prepared in the presence and absence of beta-cyclodextrin β-CD), amorphous particles with high surface area and dimensions of about 100 nm by 500 nm. The amorphous states of nanoparticles are confirmed further by XRD. The ATR-FTIR analysis confirms inclusion complex between β-CD and nanoparticles. The nanoparticles synthesized were used to develop an electrochemical sensor for phenolic endocrine disruptors by modifying the surface area of glassy carbon electrode (GCE). Electrochemical characterization of the iron oxide β-CD nano-composites, studied in 0.1 M potassium chloride (KCl) using chronoamperometry,showed that the surface concentration of the adsorbed composite material was 8.5 x 10-8 mol/cm2. Sensor analysis of bisphenol A (BPA) was carried out using cyclic voltammetry (CV) and square wave voltammetry (SWV) based on amperometric techniques which gave a linear range of 0.50 × 10-6 M to 50 × 10-6 M; limit of detection of 0.156 x 10-6 M and order of magnitude of linearity of 2.03. Hence, the sensor was further used to study 4-tert-octylphenol (TOP); the results showed that the sensitivity and the limit of detection were 11.31 nA L/mol and 0.249 x 10-6 M, respectively and order of magnitude of linearity of 2.00.