Micro- and submicro-scale iodimetric determination of antimony(III) in antibilharzial compounds by use of amplification reactions

Abstract

Simple, rapid and highly sensitive iodimetric amplification methods are described for the micro- and submicro-determination of antimony(III) in antibilharzial compounds. The methods are based on oxidation of the sample with an excess of periodate in acetate buffered medium, masking of the unreacted periodate with molybdate, and finally, iodimetric titration of the iodate that is released. Specific reactions have been found to occur for the four different compounds analysed owing to the presence, in the same molecule, of one or two antimony(III) and α-diol functions, both of which are oxidised quantitatively and simultaneously by periodate. Thus 3-, 9-, 15- and 18-fold amplification is achieved with triphenylstibine, tartar emetic, stibophen and diantimony piperazine tartrate, respectively. The total mean recovery is 99·49 per cent.