Simultaneous Square Wave Voltammetric Detection of Endocrine-Disrupting Agents Using a Nanocomposite of Magnetic Fe₃O₄ Nanorods and Poly(3,4-Methylenedioxy)aniline

In this report, the ultrasensitive simultaneous determination of bisphenol A (BPA), phenol, and 4-nitrophenol (4-NP) as hazardous phenolic endocrine-disrupting agents was explored by square wave voltammetry (SWV) using magnetic “needlelike” Fe₃O₄ nanorods (MNRs) and a poly­(3,4-methylenedioxy)­aniline (PMDAN) nanocomposite-modified graphite paste electrode (GPE). The MNRs had dimensions of 5.3 ± 1.1 nm in width and 61.4 ± 3.3 nm in length. A solid-state, green, and sustainable method incorporating mechanochemical reactions between 3,4-(methylenedioxy)­aniline as a novel aniline monomer and Fe­(III) chloride was used for the synthesis of MNR-PMDAN. The MNR-PMDAN nanocomposite-modified GPE (MNR-PMDAN/GPE) exhibited three well-defined anodic peaks at 0.82, 0.96, and 1.20 V vs Ag/AgCl for BPA, phenol, and 4-NP, respectively, in an acidic electrolyte solution at pH 2.0. The calibration curves were linear up to 40.0, 150.0, and 125.0 μM with a limit of detection of 4.3, 15.3, and 16.8 nM for BPA, phenol, and 4-NP, respectively. MNR-PMDAN/GPE was also used for the determination of BPA, phenol, and 4-NP in real samples with recoveries in the range of 95.2–104.9%. The results of this study demonstrate that the MNR-PMDAN nanocomposite is suitable for applications toward the development of a handheld device for on-field prescreening of hazardous endocrine-disrupting pollutants.