Determination of paraben-, isothiazolinone- and alcohol-type preservatives in personal care products by HPLC with dual (diode-array and fluorescence) detection

A high-performance liquid chromatography (HPLC) method with two in-line detectors has been developed for detection and quantification of preservatives in personal care products. Five of the most common preservatives in cosmetics, methylisothiazolinone (MIT), chloromethylisothiazolinone (CMIT), 4-hydroxybenzoic acid (HBA), phenoxyethanol (PE) and methylparaben (MP) were selected as target compounds. UV-visible and fluorescence spectra of these compounds at different pH values were registered to optimize detection conditions using both, diode array (DAD) and fluorescence (FLD) detectors. The optimal separation was achieved using an acetonitrile acetate buffer (0.05 mol L-1, pH 4) mobile phase with a gradient elution program. The limits of quantification are far below the established levels in the European Regulations for these compounds in cosmetic products. The method has been successfully applied to analyse different types of personal care products such as facial tonics, mouthwashes, shampoos, hair sprays, hair conditioners or body creams. A simple sample pre-treatment was performed before the chromatographic analysis. The dual diode-array and fluorescence detection allows the reliable identification and quantification of these preservatives using a unique sample extract even if they are at very different concentration levels.

Automated summary

A high-performance liquid chromatography (HPLC) method with two in-line detectors was developed for the detection and quantification of preservatives in personal care products. The method successfully analyzed various types of personal care products containing common preservatives.