Simpler liquid-chromatographic screening for organic acid disorders.

We describe an isocratic cation-exchange chromatographic technique, with ultraviolet detection, for determination of urinary organic acids. The method is useful for screening urines from neonates and infants suspected of having an organic aciduria, prior to confirmatory analysis by gas chromatography-mass spectrometry. Advantages of this technique over conventional gas chromatography include ease of sample preparation and the simultaneous detection of volatile fatty acids; limitations include its lack of an identification system like that of mass spectrometry, the presence of nonultraviolet-absorbing fatty acids, and the relatively long retention times of phenolic compounds. Chromatograms for patients with methylmalonic aciduria, propionic aciduria, isovaleric aciduria, beta-ketothiolase deficiency, lactic aciduria, and glutaric aciduria type II are compared with those for a normal infant.