Liquid chromatographic determination of erythromycins in fermentation broth

A simple and sensitive isocratic LC method is described for the determinati on of erythromycins in fermentation broths. A simple technique utilizing ac etone-methyl ethyl ketone, 1:1, as extraction solvent was coupled with suit able chromatographic conditions - compounds were separated on a 250 mm x 4. 6 mm i.d., 5 mum, reversed-phase column at 65 degreesC with acetonitrile-0. 2 M K2HPO4 pH 7.0-water, 35:5:60 (v/v), as mobile phase at a flow rate of 1 .0 mL min(-1). UV detection was performed at 215 nm. Separation of erythrom ycin F from polar components of the fermentation liquid was sufficient. Ery thromycins A, B, C, D, and E, and N-desmethylerythromycin A were also separ ated, as were known decomposition products of erythromycin A and several un known components. The method is suitable for monitoring the progress of ery thromycin fermentation.