ANALYTICAL APPROACH IN DIAGNOSIS OF INHERITED METABOLIC DISEASES - MAPLE-SYRUP-URINE-DISEASE (MSUD) - SIMULTANEOUS ANALYSIS OF METABOLITES IN URINE BY ENANTIOSELECTIVE MULTIDIMENSIONAL CAPILLARY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY (ENANTIO-MDGC-MS)

Maple Syrup Urine Disease (MSUD) is an autosoma) recessive inherited m etabolic disorder of branched chain amino acid (L-valine, L-leucine, a nd L-isoleucine) metabolism named after the characteristic smelt of af fected patients urine. MSUD is caused by a deficiency of the branched- chain alpha-keto acid dehydrogenase complex resulting in an accumulati on of branched-chain amino acids and the corresponding alpha-keto- and alpha-hydroxy acids in blood, urine and cerebrospinal fluid causing n eurological damage and mental retardation. The enantioselective analys is of chiral MSUD metabolites and analysis of achiral compounds as cor responding N,O-methoxycarbonyl methyl esters by derivatization with me thyl chloroformate (MCF) has been achieved simultaneously by enantiose lective multidimensional gas chromatography-mass spectrometry using he ptakis yl-6-O-tert-butyl-dimethylsilyl)-beta-cyclodextrin as chiral st ationary phase. Derivatization with MCF allows the analysis of the str ucturally different metabolites such as branched-chain-carboxylic-, al pha-oxo-, alpha-hydroxy- and alpha-amino acids in a single chromatogra phic run. Mass selective detection immensely improves the unequivocal identification of metabolites even when they occur as trace compounds. The described method allows a reliable screening of MSUD metabolites in patients' urine without time consuming sample preparation and is al so suitable for label enrichment analysis without any methodical chang es. During this investigation urine samples from three MSUD patients w ere analyzed.