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Quantification of human amniotic fluid constituents by high resolution proton nuclear magnetic resonance (NMR) spectroscopy
Author(s) -
Sims Cynthia J.,
Fujito Don T.,
Burholt Dennis R.,
Dadok Josef,
Giles Harlan R.,
Wilkinson D. Allan
Publication year - 1993
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.1970130609
Subject(s) - amniotic fluid , chemistry , nuclear magnetic resonance spectroscopy , valine , phenylalanine , proton nmr , nmr spectra database , alanine , spectroscopy , histidine , proton , leucine , amniocentesis , nuclear magnetic resonance , chromatography , amino acid , spectral line , fetus , biochemistry , pregnancy , stereochemistry , prenatal diagnosis , biology , genetics , physics , quantum mechanics , astronomy
Abstract We have investigated the ability of high‐resolution proton NMR spectroscopy to provide a biochemical constituent screening of human amniotic fluid (AF). Proton NMR spectra were obtained at 300 MHz on AF from patients undergoing amniocentesis in the mid‐trimester. Only AF from normal pregnancies (normal fetal karyotype, normal a‐fetoprotein levels, normal birth outcome) was used in this study. The AF supernatant was lyophilized and resuspended in deuterated water containing 0.1 mm phosphate buffer and 6.02 mm disodium maleate. Identification of low molecular weight compounds was confirmed by two‐dimensional NMR spectra (primarily correlated spectroscopy, or COSY) and standard addition techniques. A broad profile of compounds were ‘NMR visible’ in a single proton spectrum, including creatinine, glucose, organic acids (acetate, citrate, and lactate) and several amino acids (alanine, histidine, leucine, phenylalanine, tyrosine and valine). The proton spectrum was unaffected by prior freezing/thawing of AF samples. We were able to quantify compounds by comparison with an added concentration standard (maleate) at concentrations as low as 30 μm. Good agreement with literature values based on other analytical techniques was obtained.