SPECTROPHOTOMETRIC DETERMINATION OF PERIODATE OR IODATE IONS BY LIQUID-LIQUID-EXTRACTION AS AN ION-PAIR USING TETRAMETHYLAMMONIUM IODIDE

A simple and accurate extractive spectrophotometric procedure was deve loped for the microdetermination of periodate and iodate in aqueous me dia. The determination of periodate was based upon the extraction of t he ion-pair formed between the periodate and tetramethylammonium iodid e at pH 4 in chloroform followed by direct spectrophotometric measurem ents 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 determine d. Iodate could be determined quantitively by the proposed procedure a fter oxidation to periodate with potassium persulphate. The effect of the diverse ions on the determination of the periodate and/or iodate b y the proposed procedures was also investigated. The application of th e method for the analysis of iodate or periodate in the artificial fre sh water was successfully carried out.