Validation of an analytical procedure for the determination of oxidative hair dyes in cosmetic formulations.
A high range and variety of cosmetic formulations that contain oxidative hair dyes and matrix-forming compounds have been industrially developed over recent years and are now available on the international market. Member states of the European Union are responsible for conducting analyses of cosmetic products as deemed necessary by law and European regulation enforcement. Therefore, inspection authorities as well as the cosmetics trade and industry need validated analytical methods for the identification, characterization, and/or quality control of specific active ingredients or formulations with the aim of implementing the European Union Cosmetic Directives (76/768/ECC, 95/17/EC). In this frame, we validated a candidate reference method that enables the identification and quantification of hair dye-forming compounds. This method consists of a separation by RP-HPLC coupled with a DAD after a liquid-liquid extraction procedure for separating matrix components from the dye-forming compounds. The validation of the method includes common criteria such as the repeatability of the analysis and the establishment of figures of merit, as well as statistical evaluations and quality assurance in order to follow the recommendations of the Eurachem guide for analytical measurements.
An efficient and rapid thin‐layer chromatography method for the identification of 32 dye substances in hair dye products
The use of dye substances in hair dye products has led to controversial public and scientific discussions about their impact on human health. This study aimed to explore a rapid method for identification of dye substances in hair dye products.
Chromatography on Poly-RP and its cyano and diol derivatives using both polar and non-polar solvent systems
Abstract A 4-μm polystyrene-divinylbenzene resin, Poly-RP CO, was synthesized for high-performance liquid chromatography. The surface of this resin was functionalized with cyano and diol groups that are capable of enhancing the selectivity and capacity of the base resin. Chromatography was performed with traditional polar solvent systems, such as acetonitrile-water, and also with non-polar solvent systems, such as dichloromethane-hexane; the latter solvent system can give separations that are otherwise difficult to achieve with acetonitrile-water. Good separations of simple isomer mixtures were achieved on these resins.