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 zon e electrophoresis method (CZE) have been developed for the analysis of meth ylparaben, ethylparaben, propylparaben and butylparaben in a commercial cos metic product. A Very simple extraction procedure with acidified diethyleth er was developed. The HPLC method involved a C18 reversed-phase column and a gradient of methanol and water-acetic acid (1%). Electrophoretic separati on 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 lin ear from 1 to 40 mu g/ml in HPLC and from 5 to 200 mu g/ml in CZE. The limi t of detection in CZE (0.21 mu g/ml) was higher than in HPLC (0.05 mu g/ml) . Repeatability and intermediate precision were satisfactory for both metho ds (RSD Values < 3.23% in HPLC and < 3.26% in CZE). Only HPLC allowed the s eparation of butylparaben isomeric forms when CZE analysis was less time an d reagents consuming. These results suggest that HPLC and CZE coupled with a simple extraction process are both suitable for parabens determination in cosmetic products. (C) 2000 Elsevier Science B.V. All rights reserved.