HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ANALYSIS OF MEVINOLIN AS MEVINOLINIC ACID IN FERMENTATION BROTHS

High-performance liquid chromatographic analysis of mevinolin in fermentation broth was initially performed after addition of acid and extraction with methanol using a mobile phase at pH 3.0. Under such conditions mevinolin was present in three different forms: as a lactone, as the corresponding beta-hydroxy acid (mevinolinic acid) and as its methyl ester. To achieve accurate and reproducible results the method was modified such that only one form was present: mevinolinic acid. The fermentation broth samples were adjusted to pH 7.7 before the extraction with methanol, and the pH of the mobile phase was adjusted to 7.7 as well. For the separation a 250 x 4 mm I.D. column, termostated at 40 degrees C, packed with Spherisorb ODS 2 of 5 mu m particle size was used. Under these conditions mevinolin was detected at 237 nm as a single peak of a beta-hydroxy acid, which has the lowest retention time of all three forms.