Chromatography of microbial metabolites of aromatic amino acids

A mixture of hydroxy-, methoxy- and aminobenzenecarboxylic acids (aromatic acids) was studied by gas (GC) and liquid (LC) chromatography. The gas and high-performance liquid chromatographs were attached to a computer. The GC method yielded elution data for trimethylsilyl derivatives of a large number of aromatic acids on four stationary silicone phases, OV-1, SE-52, OV-17 and 1,5-bis(m-phenoxyphenyl)-1,1,3,3,5,5-hexaphenyltrisiloxane. HPLC measurements afforded capacity factors, k, for these aromatic acids on a reversed stationary phase as a function of the mobile phase composition, which consisted of methanol (or ethanol), water and acetic acid. The GC and LC separation systems were described by an empirical function, embodying parameters such as the resolution, R, standard deviation, s, analysis time, t, and time for preparative work, tp. Evaluation of the optimization function enabled assessment of the applicability of the chromatographic methods to the analysis and isolation of natural metabolites of aromatic amino acids from microbial material.