Anion-exchange resin modified with bismuthiol-II, as a new functional resin for the selective collection of selenium(IV). 
A functional resin for the collection of selenium(IV) has been prepared simply by the conversion of a common ion-exchange resin with bismuthiol-II which has three functional properties, namely the capabilities of selective reaction with selenium(IV), ion-exchange reaction with ion-exchange resin and strong physical sorption to the ion-exchange resin matrix.  The binding ratio of selenium(IV) to bismuthiol-II on the resin was confirmed to be 1:4.  The reaction was represented as follows: 4RSH + H(2)SeO(3)--> R-S-Se-S-R + R-S-S-R + 3H(2)O. Highly selective sorption of selenium(IV) was achieved, based on the formation of stable selenotrisulphide on the resin.  Selenium(IV) sorbed on bismuthiol-II resin was eluted effectively with 8-13M nitric acid or some thiols, such as cysteine and penicillamine.  In the cases of thiols, the elution of selenium was found to be also based on the formation of selenotrisulphide, and the bismuthiol-II resin was regenerated.  Satisfactory results were obtained when this resin was applied to the determination of selenium(IV) in river, estuarine or sea water samples.