Determination of preservatives in cosmetic products by ion-pair reversed-phase high-performance liquid chromatography. III

HPLC determination of chlorhexidine gluconate and p-chloroaniline in topical ointment

A novel fast isocratic reversed-phase HPLC method for simultaneous determination of chlorhexidine and its degradation product p-chloroaniline was developed. Zorbax SB Phenyl column (75 mm x 4.6 mm, 3.5 microm) was used for the separation. Mobile phase composed of acetonitrile and buffer solution of 0.08 M sodium phosphate monobasic containing 5 ml of triethylamine (0.5%) and adjust with 85% phosphoric acid to pH 3.0 in ratio 35:65 (v/v) pumped isocratically at flow rate 0.6 ml min(-1) was used. UV detection was performed at 239 nm, the total analysis time was about 10 min. The method is suitable for practical routine analysis of topical ointment in the quality control laboratory.

Determination of preservatives in cosmetic products. II. High-performance liquid chromatographic identification

A high-performance liquid chromatographic (HPLC) procedure is presented for the separation and identification of preservatives that are listed in the current EEC Council Directive on cosmetic products or have been permitted in the past. The method consists of an extraction of acidified cosmetics with methanol, and separation of the extracts by HPLC. Using two isocratic and two gradient reversed-phase HPLC systems, 47 preservatives were characterized by their retention times. The preservatives in three commercial cosmetic products were tentatively identified by the procedure described. The HPLC procedure is suitable for confirmation of the presence of preservatives in cosmetic products as indicated by a previously reported thin-layer chromatographic procedure. In general this method will permit the routine detection of preservatives in cosmetics in an approximate concentration of 0.01% (w/w).