CTAC Self-Assembled\nAlkylated β‑Cyclodextrin\nLoaded onto Functionalized MWCNTs Electrochemical Sensor for NP Detection

Nonylphenol (NP) is an important fine chemical raw material\nand\nintermediate that is widely utilized in industry and may be distributed\nin aquatic ecosystems. Following its entry into the food and water\ncycles, it can subsequently enter the human body and potentially harm\nthe human reproductive system. For the purpose of monitoring NP in\nwater, it is thus essential to build a straightforward, affordable,\nand robust electrochemical sensor. Based on a two-step chemical modification\nproceeding and an electrostatic self-assembly effect, a double-modified\nβ-cyclodextrin functionalized multiwalled carbon nanotube sensor\n(HE-β-CD-CTAC/F-MWCNTs) has been successfully constructed. It\nincorporates the excellent host–guest interaction ability of\nβ-cyclodextrin and the high chemical activity of cetyltrimethylammonium\nchloride (CTAC), and the carbon nanotubes have an enormous particular\nsurface area and strong electrical conductivity. The electrochemical\noxidation reaction of NP with the sensor is controlled by a surface\nadsorption process of equal numbers of protons and electrons. In accordance\nwith the optimized experimental parameters, the limit of detection\n(LOD) for the sensor is 0.13 μM, and it responds linearly to\nNP in the concentration range of 1–200 μM. Meanwhile,\nthe sensor has excellent repeatability, stability, and immunity to\ninterference. For the detection of NP in real water samples, the sensor\nalso showed an excellent recovery rate (92.8%–98.5%) and relative\nstandard deviation (1.16%–3.26%).