title: Determination of free amino acids and related compounds in amniotic fluid by capillary electrophoresis with contactless conductivity detection.
abstract: A capillary electrophoretic (CE) method with contactless conductivity detection (CCD) has been developed for the determination of free amino acids (AAs) in the amniotic fluid. Apart from 20 proteinogenic AAs, 12 other biogenic compounds have been identified including ethanolamine, choline, beta-alanine, 2-aminobutyric acid, 4-aminobutyric acid, creatinine, ornithine, carnitine, citrulline, 4-hydroxyproline, 1-methylhistidine and 3-methylhistidine. The running electrolyte consisted of 1.7 M acetic acid and 0.1% hydroxyethyl-cellulose (pH 2.15). An addition of acetonitrile to the sample improved the separation of AAs significantly and permitted an increase in the amount of the sample injected. As a result, the sensitivity of the determination increased and the limit of detection (LOD) decreased by a factor of ca. 4, as compared with our previous study. The LOD values were between 1.5 microM (arginine) and 6.7 microM (aspartic acid). The CE/CCD method has then been applied to clinical analyses of the amniotic fluid collected from 20 pregnant women aged over 35 years and 24 pregnant women with whom abnormal foetus development was suspected. The latter group of women was found to exhibit systematically enhanced amniotic levels of most of the AAs studied.
authors.affiliation: Charles University, 3rd Faculty of Medicine, Centre of Biomedical Sciences, Ruská 87, 100 00 Prague 10, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Tůma
authors.forename: Eva
authors.initials: E
authors.lastname: Samcová
authors.forename: Katerina
authors.initials: K
authors.lastname: Andelová
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry*; D000653:Amniotic Fluid / Q000737:chemistry*; D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods*; D005260:Female; D006801:Humans; D011247:Pregnancy
chemical_list: D000596:Amino Acids