[Gas chromatographic estimation of acidic urinary metabolites after separation on prepacked silica gel columns (author's transl)].

The acidic ethylacetate extracts of 24-h urine specimens are evaporated and redissolved in chloroform--methanol--acetic acid. The resulting solution is transferred to a prepacked silica gel column. Elution takes 160 min using a specially designed chloroform--methanol--acetic acid gradient. The eluate is divided into fractions (16 min each) which are evaporated to dryness. The residues are silvlated and determined quantitatively by gas chromatography. The capacity of the silica gel column allows analysis of 30% of a 24-h urine specimen. In consequence, metabolites can be quantitated at concentrations less than 1 mg per 24 h. The method is suitable to obtain more detailed metabolic profiles of the carboxylic acids in urine.