Headspace solid-phase microextraction gas chromatography-mass spectrometry method for the identification of cosmetic ingredients causing delamination of packagings.

A headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method using a 75 microm Carboxen polydimethylsiloxane fibre was used to identify volatile compounds of cosmetic formulations responsible for causing loss of adhesion between layers of multilayer packagings. To obtain the sample, the sachet with the product was kept in an oven at 40 degrees C in order to favour the migration of the aggressive compounds to the inner layers. Then the sachet was manually delaminated and the aluminium/polyester and polyethylene layers were analysed. The cosmetic product was also analysed by HS-SPME-GC-MS. Several compounds used in the cosmetic industry such as perfumes or fixing agents were detected in the inner layers of the laminated material, showing the migration of them through the layer in contact with the product (polyethylene). Phenoxy ethanol, beta-linalool, menthol and p-propenylanisole are suspected to be responsible for the loss of adhesion. In order to provide a complete overview of the cause of the aforementioned phenomenon, the packaging material was exposed to the cosmetic products in order to measure the decrease of the adhesion strength with time. It was observed that the product with a higher phenoxy ethanol concentration caused a higher loss of adhesion strength. The results obtained showed that this method is suitable for identifying aggressive compounds in cosmetic products, as well as for giving prior information about which products may be problematic for packaging in sachets.