Comparison of high-performance liquid chromatography and capillary zone electrophoresis for the determination of parabens in a cosmetic product.

A high-performance liquid chromatographic method (HPLC) and a capillary zone electrophoresis method (CZE) have been developed for the analysis of methylparaben, ethylparaben, propylparaben and butylparaben in a commercial cosmetic product. A very simple extraction procedure with acidified diethylether was developed. The HPLC method involved a C18 reversed-phase column and a gradient of methanol and water-acetic acid (1%). Electrophoretic separation was performed on a fused-silica capillary with a mixed 15 mM tetraborate buffer (pH 9.2) and methanol (85:15, v/v). The calibration curves were linear from 1 to 40 microg/ml in HPLC and from 5 to 200 microg/ml in CZE. The limit of detection in CZE (0.21 microg/ml) was higher than in HPLC (0.05 microg/ml). Repeatability and intermediate precision were satisfactory for both methods (RSD values < 3.23% in HPLC and < 3.26%, in CZE). Only HPLC allowed the separation of butylparaben isomeric forms when CZE analysis was less time and reagents consuming. These results suggest that HPLC and CZE coupled with a simple extraction process are both suitable for parabens determination in cosmetic products.