Application of Graphene as Solid Phase Extraction Absorbent for the Determination of Parabens in Cosmetic Products by Capillary Electrophoresis

A graphene-based solid phase extraction (SPE) technique was developed for the extraction of parabens (methylparaben, ethylparaben, propylparaben, and butylparaben) in cosmetic samples, followed by determination by capillary electrophoresis (CE). The SPE extraction parameters such as eluent reagent and eluent volume, washing solution, sample pH, and flow-rate of sample loading, were investigated for satisfied recoveries. The running buffer, consisting of 25mM borate solution (pH 10.0), was used for the separation of four parabens with the CE method within 10min. The limits of detection were 0.14mg/L, 0.13mg/L, 0.15mg/L, and 0.10mg/L for methylparaben, ethylparaben, propylparaben, and butylparaben, respectively, and the mean recoveries obtained were between 62.6% and 100.4%. The developed method was used for the determination of parabens in real cosmetic products.