The extraction of bismuth has been investigated in dependence of dilution and stoichiometry, using the reagents 8-hydroxyquinoline,
N-benzyl-N-phenylhydroxylamine, diphenylthiocarbazone and substituted carbamates. Stripping of bismuth from organic solutions
of the respective chelates using ligands such as EGTA, thioglycollic acid and 2,3-dimercaptopropane-1-sulfonate was also studied.
It has been demonstrated that the equations proposed for determining the range of quantitative substoichiometric extraction
are valid in the case of bismuth only at concentrations above 10−5 M Bi. At further dilutions (10−6–10−8 M), which would be of major interest in devising analytical methods based on the substoichiometric radioisotope dilution
technique for determining bismuth at the trace level, the equilibria are shifted in favour of the competing hydrolytic reactions,
so that the extraction is quantitative only with ammonium tetramethylenedithiocarbamate present in excess.