Spectrophotometric determination of periodate or iodate ions by liquid-liquid extraction as an ion-pair using tetramethylammonium iodide

摘要

A simple and accurate extractive spectrophotometric procedure was developed for the microdetermination of periodate and iodate in aqueous media. The determination of periodate was based upon the extraction of the ion-pair formed between the periodateand tetramethylammonium iodide at pH 4 in chloroform followed by direct spectrophotometric measurements at 509, 358 and 288 nm. The optimum concentration range evaluated by Ringbom's plot, the molar absorptivity, the Sandell's sensitivity and the stoichiometry of the formed ion-pair were critically determined. Iodate could be determined quantitively by the proposed procedure after oxidation to periodate with potassium persulphate. The effect of the diverse ions on the determination of the periodate and/or iodate by the proposed procedures was also investigated. The application of the method for the analysis of iodate or periodate in the artificial fresh water was successfully carried out.