Subiect: The work presents aspects regarding the significance of icons, the way they are made, the integrant elements, as well as the methods of scientific expertise. The chemical methods of the quality analysis (spot test) is based on different chemical reactions, while the physical-chemical ones on the measuring of some physical and chemical characteristics with the help of certain instruments. In this category are mentioned UVVIS and IR spectroscopy, the chromatography, the fluorescence spectrometry of X rays, electronic microscopy and optical microscopy.
