[Absorption spectrum of admixtures coloring butyl acetate extract].

Colour of butyl acetate extract (BAE) at the clarification stage in chemical purification of benzylpenicillin is one of the important qualitative parameters necessary for the process control. BAE is benzylpenicillin-enriched butyl acetate with colouring pigments and admixtures of unknown nature. The routine laboratory photocolorimetric method provides only periodical control. It is labour-consuming and does not enable determination of the process end. The specific characteristics of the butyl acetate extracts and their components in UV and visible spectra were studied and the absorption region of the admixtures (350-500 nm) colouring the extract with a maximum at 390 +/- 10 nm was determined. A photometric method, a definite wave length and analyzer Luch-II are recommended for optimal control of the clarification process. The apparatus was tested under laboratory conditions.