Spectrofluorometer Fluorolog FL 3-12 Spex-Jobin-Yvon is an excellent instrument to make photoluminescence measurements. It is possible to get emission and excitation spectra of miscellaneous luminescence centers which are present in inorganical and organical compounds, natural or synthetic, for solid – i.e. crystals, powders, thin layers or for liquid samples. It is possible to identity such luminescence centers as 3dn or 4f ions. The crystalochemical analysis – site symmetry and type of coordination ions is possible, too. We can also measure  the aromatic compounds in solid and liquid state; among them- carcinogens in environmental samples (free radicals, benzopyrene and their derivatives)  to molar concentration 10-4. It is possible to value the relative quantum luminescence efficiency. The measurement are made in room and liquid nitrogen temperatures. As this instrument is not furnished with microscope, the studied samples’ diameter should be larger than 1 mm. The photoconductivity measurements can be make as well.