Reverse phase high performance liquid chromatography (HPLC) was used as a rapid means of monitoring the erythromycin and the tetracycline fermentation processes. The sample preparation process for tetracycline in the fermentation broth includes simple dilution and filtration through a Millipore filter prior to injection into the HPLC column. Fermentation broth samples showed no interference, and excellent separation for selective determination of tetracycline, 4-epitetracycline, anhydrotetracycline, chlortetracycline, and 4-epianhydrotetracycline was obtained. The relative standard deviation for the HPLC analysis for tetracycline is about one percent and the correlation coefficient between the HPLC and the spectrophotometric assay methods is better than 0.994.
The sample preparation procedure for erythromycin determination in fermentation broth requires solvent cleanup and extraction processes. The chromatographic analysis takes approximately 25 minutes, and the HPLC method is capable of separating and quantifying erythromycins A, B, C, and various epimers and degradation compounds. The correlation coefficient between the HPLC and the microbiological assay method is 0.970.