Abstract

We report on a simple and highly sensitive square wave voltammetric method for the determination of methylparaben (MP) using a pencil graphite electrode (PGE) modified with gold nanoparticles and activated carbon/graphene oxide (denoted as AuNP@AC/PGE and AuNP@GO/PGE). The modified electrodes display enhanced electroactivity and antifouling for the oxidation of MP compared to the unmodified PGE. Under optimized conditions, both types of the modified electrode exhibit similar efficiency in terms of the linear response to MP in the concentration range between 0.030 and 1.0 mM, high reproducibility (RSD of 3.44–3.51%), and repeatability (RSD of 2.79–3.36%). However, the AuNP@GO/PGE (2.02 μM) provided a better limit of detection than the AuNP@AC/PGE (2.17 μM). In addition, the modified electrodes also have a remarkably stable response, and up to 30–40 analyses are possible at 0.2 mM of MP. Additionally, the sensors provided acceptable recoveries ranging from 85 to 110% for the samples spiked with MP from four types of cosmetics. In addition, the results agreed with those obtained from conventional high performance liquid chromatography coupled with diode array detection.