Abstract:
The aim of this study was to develop systems for the rapid electrochemical determination of BPA and NP based on biopolymer membranes with agarose and green tea condensed tannins onto gold electrodes.
In the first part of the study, the GT-Agar/Au sensor, an electrochemical sensor based on green tea condensed tannins incorporated into an agarose matrix, was developed to determine bisphenol A.
AFM, FTIR, SEM, and HPLC techniques were used to purify and characterize green tea tannins. Various electrochemical measurements, such as electrochemical impedance spectroscopy(EIS), cyclic voltammetry(CV), and square wave voltammetry(SWV), are also conducted to assess the electrochemical activity of GT-Agar/Au sensors. The proposed sensor has been successfully applied to determine BPA levels in bottled water samples at ultra-trace concentrations with satisfactory recovery rates, instilling confidence in its effectiveness. The results are highly reliable when compared with HPLC results.
In the second phase of this study, we investigated the potential of modifying these molecules to enhance their performance by introducing novel functionalities. Specifically, an amine (-NH₂) functional group.The amine-functionalized condensed tannins were characterized structurally using Fourier transform infrared spectroscopy (FTIR) and morphologically with scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy (AFM).Then,it was immobilized onto an agarose matrix to develop an electrochemical sensor for detecting nonylphenol (NP). Their electrochemical properties were evaluated using cyclic voltammetry (CV) and square wave voltammetry (SWV).
The newly developed sensor, GT-NH2-Agar/Au, demonstrated significant electrochemical activity toward nonylphenol. This sensor was applied to detect nonylphenol in river water samples, and the results were validated against high-performance liquid chromatography (HPLC), showing strong agreement. This approach successfully developed a rapid, accurate, and efficient electrochemical assay for detecting nonylphenol in environmental water samples.
