Monoamine metabolites and related compounds in human amniotic fluid: assay by gas chromatography and gas chromatography-mass spectrometry.

Some catecholamine metabolites and related compounds have been identified in amniotic fluid obtained by transabdominal amniocentesis at various stages of pregnancy, including 4-hydroxy-3-methoxymandelic acid, 4-hydroxy-3-methoxyphenylglycol, 4-hydroxy-3-methoxyphenylcetic acid, p-hydroxypheny lacetic acid, p-hydroxphenyllactic acid and N-benzoylglycine (hippuric acid). Analysis was by gas chromatography with electron capture detection and by gas chromatography-mass spectrometry. Two of these compounds were determined quantitatively, free 4-hydroxy-3-methoxphenylglycol and p-hydroxyphenllactic acid: the concentration of the former increased with advancing pregnancy and that of the latter tended to decrease. Conjugated 4-hydoxy-3-methoxyphenylglycol could not be determined with accuracy as appreciable amounts of the unconjugated compound were found in the snail extract used for enzymatic hydrolysis. Assay of 4-hydroxy-3-methoxyphenylglycol in amniotic fluid is likely to be of diagnostic importance in the prenatal diagnosis of congenital neuroblastoma. Although 4-hydroxy-3-methoxyphenylethanol, 3, 4-dihydroxymandelic acid and 3, 4-dihydroxyphenylacetic acid were specifically looked for in amniotic fluid, they could not be detected.