Methodologies for the analytical determination of ferrate(VI): A Review

This paper reviewed different analytical techniques to determine concentrations of the environmentally-friendly oxidant ferrate(VI) (FeVIO2-4, Fe(VI)) anion in solid and solution samples. The techniques included volumetric (chromite and arsenite), electrochemical (cyclic voltammetry and potentiometry), and spectrophotometric methods (Fourier transform infrared, Mossbauer, UV-Visible, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonate (ABTS), and fluorescence). The importance of the techniques were briefly described. This paper also presented a newly developed method for the determination of low concentrations (0.25 M) of Fe(VI)) using the reaction between Fe(VI) and iodide (I-), which formed the yellowish color of I-3 that could be measured spectrophotometrically at 351 nm. The increase in I-3 was linear with respect to Fe(VI) added (0.25-76 M) in buffered solutions at pH 5.5-9.3. The linearity was not affected by the ions present in tap water.