Aqueous two-phase systems allow partition of metal ions in nondenaturing conditions. From the fresh skim bovine milk spiked
with212Pb and agitated with 4% water solution of apple pectin (degree of esterification-70%), less than 2.3% is recovered to the
pectin phase and in the case of pasteurized milk less than 3.0%. Complexation with chelate forming agents was studied. Aminoacids
as glycine, alanine and histidine do not exert influence on the yield, but the recovery in the pectin phase was 22% for cysteine,
and 80% in the case of EdtacalTM (calcium salt of ethylenediaminetetraacetic acid). The retention of lead in milk phase is extraordinarily high as compared
to strontium and corresponds to the behavior of trivalent ions.