Gas chromatographic-mass spectrometric screening for organic acidemias using dried urine filter paper:: determination of α-ketoacids

There are several organic acid disorders that require information on a-ketoacids. such as maple syrup urine disease or alpha -ketoadipic acidemia. The recovery, stability and diagnostic availability of alpha -ketoacids in dried urine filter paper analyzed by GC-MS with oxime-trimethylsilyl derivatization was studied for organic acidemia screening. The recovery of all nine types of alpha -ketoacids tested, but for phenylpyruvate, 2-ketoadipate. and p-OH-phenylpyruvate. from filter paper samples was acceptable. The stability of pyruvate, branched-chain ol-ketoacids. alpha -ketoadipate and alpha -ketoglutarate was stable for at least 28 days, although some alpha -ketoacids such as succinylacetone were unstable. It indicated it was difficult to diagnose only tyrosinemia type 1 among nine specimens from organic acidemia patients tested. The method could be applied to global organic acidemia screening. (C) 2001 Elsevier Science B.V. All rights reserved.