Electrochemical determination of butylhydroxyanisole (BHA) using a carbon fiber microelectrode modified by electrodeposition of gold nanoparticles and poly-NiTSPc film

We present an approach on the electrodeposition of gold nanoparticles (AuNPs) on a carbon fiber microelectrode (CFME) followed by deposition of nickel(II) tetrasulfonated phthalocyanine (p-NiTSPc) film by electropolymerization to form CFME-AuNPs/p-NiTSPc, for the sensitive determination of butylhydroxyanisole (BHA) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) were used to characterize the topography, morphology, and elemental composition of CFME, CFME-AuNPs, CFME-p-NiTSPc, and CFME-AuNPs/p-NiTSPc, respectively. Additionally, the electrochemical impedance spectroscopy (EIS) technique was employed to evaluate the charge-transfer rate of the tested sensors. To establish the optimal conditions for the electroanalysis of BHA, various parameters were investigated, including the potential scan rate, pH, and electrolysis potential. CFME-AuNPs/p-NiTSPc demonstrated the highest BHA signal, corresponding to the highest active surface area of 0.025 cm2, compared to CFME-p-NiTSPc (0.024 cm2), CFME-AuNPs (0.022 cm2), and CFME (0.021 cm2). In a phosphate buffer solution (PBS, 0.1 M; pH 3), a good linear relationship (R2 = 0.998) was observed between peak current intensities and BHA concentrations in the range of 10–80 µM, resulting to a detection limit (LOD) of 3.60 µM (S/N = 3) and a quantification limit (LOQ) of 12 µM (S/N = 10). The analytical HPLC technique was also tested for BHA determination within the concentration range of 5.55–55.48 µM and the obtained LOD was calculated to be 4.41 µM. The potential interference of certain species that could affect the BHA oxidation signal was also evaluated, followed by the application of CFME-AuNPs/p-NiTSPc in real water and Mitosyl ointment samples. The recovery values of BHA were acceptable, ranging from 96 to 99