HPLC method with electrochemical detection on gold electrode for simultaneous determination of different antimicrobial agents in cosmetics.

[Display omitted] • Good electrochemical responses due to biocide oxidation on gold electrode. • The first HPLC-ECD method with gold electrode for biocide determination. • Good analytical features to control the amount of antimicrobial agents in cosmetics. • Successful results in cosmetic analysis with the HPLC-ECD method. Antimicrobial agents are added to a wide variety of products such as cosmetics to reduce the risk of microbial contamination and ensure the suitability and safety of the product. However, recent studies have shown that these compounds can have negative effects on human health and the environment. Therefore, it is crucial to develop analytical methods to control the amount of these compounds in personal care products to guarantee human health and product quality. This paper presents an HPLC method with electrochemical detection using a gold electrode for the determination of the most used antimicrobial agents in cosmetic products: methylparaben (MP), 4-hydroxybenzoic acid (4-HBA), phenoxyethanol (PE) and methylisothiazolinone (MIT). For this purpose, the electrochemical response of these compounds was evaluated on the gold electrode. The optimal electrochemical detection of MP, 4-HBA; PE and MIT was performed at pH 2 and + 1.50 V (vs Ag/AgCl). Under the optimal separation and detection conditions, limits of detection (LODs) between 10 and 110 μg L−1 were obtained. These LODs are lower than those previously reported for other HPLC methods with mass spectrometry and diode-array detectors. Cosmetic products with different compositions were successfully analysed with the proposed HPLC method obtaining recoveries between 76 % and 119 %. [ABSTRACT FROM AUTHOR]