Patent ID: 7553461

Claim:
A method for separating a predetermined multivalent cation having a crystal ionic radius of about 0.8 to about 1.2 Angstroms (Å) from an aqueous sample comprising the steps of: (a) contacting a separation medium with an aqueous sample containing an acid or salting out amount of one or more acids or salting out agents for a neutral extractant and dissolved multivalent cations, including said predetermined multivalent cation, said separation medium comprising a diglycolamide extractant corresponding in structure to Formula I dispersed onto a porous inert resin or silica support, wherein R 1 , R 2 , R 3 and R 4 are the same or different and are hydrido or hydrocarbyl groups such that R 1 +R 2 +R 3 +R 4 contains about 14 to about 56 carbon atoms; (b) maintaining said contacting for a time period sufficient for the predetermined multivalent cations to be extracted from the aqueous sample to the separation medium to form a solid phase loaded separation medium and a liquid phase multivalent cation-depleted sample; and (c) separating said solid and liquid phases.