Fabrication of highly sensitive Bisphenol A electrochemical sensor amplified with chemically modified multiwall carbon nanotubes and β-cyclodextrin

Bisphenol A (BPA), one of the most extensively used plasticizers, is an endocrine disrupting chemical (EDC). Leaching of BPA in food, and water sources causes adverse health effects, therefore, it requires monitoring. In this work, we developed a simple, low-cost electrochemical sensor for detecting a very low level of BPA in water using chemically modified multiwall carbon nanotubes (MWCNTs) with beta-cyclodextrin (beta CD) on screen-printed carbon electrode (SPCE). The electrochemical sensing of BPA showed a completely irreversible process with diffusion-controlled oxidation involving two electrons and two protons. At an optimized condition, the sensor showed a two-step linear response from 125 nM to 2 mu M and 2 to 30 mu M, with correlation coefficients of 0.997 and 0.995, respectively. The limit of detection for BPA was determined to be 13.76 nM (SNR = 3). The improved sensing performance is attributed to host-guest interaction ability of MWCNTs- beta CD with BPA due to the combined effect of hydrophilic behavior of beta CD and large surface area of MWCNTs. The sensors exhibited an excellent reproducibility (RSD = 4.7 %) and stable response over five weeks and negligible interference with common chemical species in water. The sensor's reliability test in lake and tap water showed an excellent recovery of BPA ranging from 96.05 %-108.70 %. These favorable results can enable the development of simple and cheap portable sensors for monitoring a wide range of BPA levels in the water.