The application of gel filtration, immunonephelometry and electrothermal atomic absorption spectrometry to the study of the distribution of copper-, iron- and zinc-bound constituents in human amniotic fluid.

Gel filtration with Sephacryl S-300 was used to fractionate copper-, iron-, and zinc-bound proteins and low molecular mass constituents in samples of amniotic fluid collected at delivery. The fractions were analysed for copper, iron and zinc by electrothermal (carbon furnace) atomic absorption spectrometry. The proteins associated with these metals were determined by immunonephelometry. The results showed that caeruloplasmin, transferrin and albumin are the major proteins that bind copper, iron and zinc, respectively. Less than 10% of the metals, except iron, recovered from the column was bound to low molecular mass constituents. Comparisons between the distribution of these elements in amniotic fluid and serum are shown and discussed.