Acetate and chloride determination by ion exchange HPLC with indirect photometric detection and its application to a beta-methylcarbapenem antibiotic

A high performance liquid chromatographic (HPLC) method, using an anion exc hange column with indirect photometric detection, was developed for the det ermination of acetate and chloride anions in the antibiotic ertapenem sodiu m. HPLC with indirect photometric detection was used due to the UV-transpar ent properties of acetate and chloride and the advantage that the method em ploys simple rugged laboratory chromatographic equipment. The challenges en countered with method optimization are discussed. The method gives baseline separation of the anions with limit of quantitati on values of 0.005 wt % and 0.006 wt % for acetate and chloride, respective ly. The method was also validated for precision, linearity, recovery, rugge dness, and solution stability.