[Trace elements in raw materials and nutrient media for cultivation of antibiotic-producing organisms]

The contents of microelements such as Fe, Cu, Zn and As in samples of raw materials including food grade ones used in preparation of nutrient media for cultivation of antibiotic-producing organism and water were determined spectrophotometrically with using complex forming organic reagents. An original procedure for the sample combustion in the assay was developed. The natural background levels of the microelements in the nutrient media used in manufacture of some antibiotics were estimated.