Abstract
A micellar electrokinetic capillary chromatography method with electrochemical detection (MECCβED) has been developed for the simultaneous determination of eight phenolic additives, including propyl gallate (PG), tertβbutylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) in cosmetic products. Method development involved optimization of the working electrode, the pH value of running buffer, the concentration of sodium dodecyl sulfate (SDS), the separation voltage, and the sample injection time. Under the optimum conditions, all analytes can be well separated within 26 min at the separation voltage of 18 kV in a 9 mmolΒ·L^β1^ sodium dodecyl sulfate (SDS) β60 mmolΒ·L^β1^ borate running buffer (pH 8.0). A 300 ΞΌm diameter carbon disk electrode generated good response at +0.90 V (vs__.__ SCE) for all analytes. Linearity of the present method was over three orders of magnitude of analyte concentration with detection limits (S/N=3) ranging from 1.1Γ10^β7^ to 1.2Γ10^β6^ gΒ·mL^β1^ for all analytes. This proposed method has been successfully applied to the simultaneous determination of the above additives in commercial cosmetics, and the assay results were satisfactory.