Abstract
At first era of the fortification, too important quantities of vitamin D were introduced in the foods and the medicinal preparations. In addition, overdoses could be explained by the simple one does that these preparations were free to reach and that certain mothers considered them as of the "tonic" and about it abused. These days, it proves himself that a big one leaves responsibility fall to the manufacturers that masteries little the method of addition and check very poorly the vitamins content D of the marketed forms.
The formations of many isomers and degradation products, as well as the presence of various sources of inherent interferences to the sample type containing vitamins D, complicating extremely the development of methods for dosage of these vitamins.
The thin layer chromatography (TLC) is the oldest chromatographic technique and the separation methods of the vitamins D by this method were comparatively numerous.