Identification des filtres UV dans les produits cosmétiques par CCM et HPLC

Synopsis The method describes the identification of 22 UV filters authorized in Cosmetic products in Europe (dir. 76/768 EEC, annex VII, modified by dir. 89/174 EEC). (Table I). Twelve UV filters registered in part 2 of annex VII (dir. 83/574EEC) provisionally allowed in 1983 were abandoned by Industry. Consequently they were suppressed from the list of UV filters which cosmetic products may contain (dir. 89/174 EEC). Nevertheless the method describes also the identification of these 12 chemicals because they could interfere with the analysis of the 22 authorized UV filters in view of similarities in chemical structures (Table I (suite)). The screening of the UV filters in final products is based on thin layer chromatography (TLC) and confirmed by high pressure liquid chromatography (HPLC/UV). TLC combines four different systems and several detection reagents: absorption chromatography on silica gel with development in a neutral solvent, an acidic solvent, a basic solvent, reversed phase chromatography on RP 18 bonded silica with development in a methanol/water mixture. The results of these screening tests are confirmed by reversed phase HPLC/UV in an isocratic elution system. The acid components and the salts which are eluted before or with the solvent peak are separated in a gradient elution system at pH 3.5. Several UV filters available on the market of cosmetic ingredients are impure chemicals or mixtures. The identification of their principal components by nuclear magnetic resonance spectrometry (NMR) and by gas chromatography/mass spectrometry (GC/MS) will be the subject of future publications.