title: Methylcitric acid determination in amniotic fluid by electron-impact mass fragmentography.
abstract: Methylcitric acid, a metabolite of abnormal propionyl-CoA metabolism, is elevated in amniotic fluid when the fetus is affected with propionic acidaemia or methylmalonic aciduria. We developed a method for quantifying methylcitric acid in amniotic fluid by solid-phase extraction, derivatisation to the t-butyl-dimethylsilylester, and gas chromatography-mass spectrometry with electron-impact ionisation, using the deuterated analogue of methylcitric acid as an internal standard. The main advantages are a good sensitivity, simple sample preparation, and feasibility on instruments equipped with mass specific detectors.
authors.affiliation: Chemisches Zentrallabor der Universitätskliniken, Inselspital, Bern, Schweiz.
authors.forename: R E
authors.initials: RE
authors.lastname: Kretschmer
authors.forename: C
authors.initials: C
authors.lastname: Bachmann
mesh_terms: D000592:Amino Acid Metabolism, Inborn Errors / Q000175:diagnosis*; D000653:Amniotic Fluid / Q000032:analysis*; D002951:Citrates / Q000032:analysis*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008314:Malonates / Q000652:urine*; D008764:Methylmalonic Acid / Q000652:urine*; D011247:Pregnancy; D011422:Propionates / Q000097:blood*
chemical_list: D002951:Citrates; D008314:Malonates; D011422:Propionates; C031605:2-methylcitric acid; D008764:Methylmalonic Acid