CLINICALCHEMISTRY, Vol.22,No.8,1976 1283 Urinary Organic Acids in Man. I. Normal Patterns

We studied qualitative pattern of urinary acidic metabolites excreted by normal persons. The results provide a basis on which to compare results for patients with potentially abnormal organic acidurias. A series of urinary polyhydroxy (aldonic and deoxyaldonic) acids has been identified. Most of these compounds have not been previously reported in human urine, except in connection with the presentwork, and are additional to the previously recognized urinary organic acids, which were also observed. Possible met-abolic origins of some of the acids are briefly dis-cussed. AddItIonal Keyphrases: DEAE-Sephadex anion-exchange chromatography #{149}endogenous and exogenous acids gas-liquid chromatography of trimethylsilyl esters and ethers #{149}acidurias #{149}inherited cflsorders of metabolism #{149}poly-hydroxy acids in urine #{149}solvent extraction There are about 50 diseases in which an inherited single enzyme defect causes a high concentration of acidic metabolites in the blood or urine (1-3). Dagleish et al. (4) proposed the use of gas chromatography for the study of the trimethylsilyl and methyl esters of organic acids extracted from physiological fluids, and reported data on a wide range of synthetic reference compounds. This work was extended to qualitative studies on urine from normal humans (5) with use of both solvent ex-traction and an anion-exchange method based on the use of diethylaminoethyl-Sephadex (6). Solvent ex-traction has also been used by many other workers [e.g., Jellum et al. (7)], but gives poor analytical recoveries of the more hydrophilic acids (2, 5). The methods used in the present work are also based on the use of DEAE-Sephadex for extraction, with stabilization of oxo-acids as ethoximes before trimethylsilylation, gas-liquid chromatography, and gas chromatography-mass spectrometry. This procedure has been quantitatively validated for a variety of organic acids (8, 9) and covers a wide range of potential urinary anionic constituents that have pKa values below about 5.5