The extraction equilibria of the ion associate of periodate with 1-(3,5-diamino-6-chloropyrazinecarboxyl) guanidine.

The extraction equilibrium of the ion-associate of periodate with 1-(3,5-diamino-6-chloropyrazinecarboxyl) guanidine hydrochloride (DPG(+)Cl(-)) was investigated spectrophotometrically. The optimum conditions for the extraction of the ion associate DPG(+).IO(4)(-) with cyclohexanone have been established. The ion association constants, beta, K(D) and K(ex) and the molar absorpativity of the formed ion associate were determined. These values enable a convenient application of the investigated system for the extraction spectrophotometric determination of periodate ions in the aqueous media. The molar ratio of the ion associate was found to be 1:1 of periodate to the reagent DPG(+)Cl(-) at pH 4-5.