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

Abstract

Abstract We report an approach to the manual manufacture of carbon fiber microelectrodes modified by electrodeposition of gold nanoparticles and nickel phthalocyanine tetrasulphonated composite (CFME-AuNPs/pNiTSPc), for the sensitive determination of butylhydroxyanisol (BHA) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Atomic force microscopy (AFM), Scanning electron microscopy (SEM) and Energy dispersive Xray spectroscopy (EDX) were used for the topographical, morphological and elemental characterizations of CFME, CFME-AuNPs, CFME-pNiTSPc and CFME-AuNPs/pNiTSPc, respectively. Furthermore, electrochemical impedance spectroscopy (EIS) technique was used to evaluate the charge-transfer rate of the tested sensors. To establish optimum conditions for the electroanalysis of BHA, various parameters were studied such as the effect of scan rate, pH and the electrolysis potential. CFME-AuNPs/pNiTSPc showed better signal of BHA with a higher active surface area of 0.195 cm2 compared to those of CFME-pNiTSPc (0.182 cm2), CFME-AuNPs (0.142 cm2) and CFME (0.130 cm2). In phosphate buffer solution (PBS 0.1M; pH 3), good linearity (R2 = 0.998) was obtained between peak current intensities and BHA concentrations in the range from 10 to 70 µM, leading to a detection limit (LOD) of 3.60 µM (S/N=3) and a quantification limit (LOQ) of 12 µM (S/N=10). The interfering effect of certain species likely to affect the BHA oxidation signal was also evaluated, followed by the application of CFME-AuNPs/pNiTSPc in real water and mitosyl ointment samples. Recovery values of BHA were acceptable ranging from 96 to 99%, indicating that the developed sensor proved to be very sensitive and effective for detecting traces of BHA.