Cosmetic products are not a simple matrix, as in their composition is present a lot of substances.
Different procedures have been adopted for their conversion into liquid form prior to analysis, which is a suitable form for introduction in the most of instruments.
The acid digestion either by conventional heating [13–22], or using microwave radiation [23–26] is the most popular of the dissolution methods of solid samples.
The problem is that these procedures, besides laborious, are slow (especially when the conventional heating is used) and require the handling of toxic and corrosive reagents