Simultaneous Kinetic-Potentiometric Determination of Iron(III) and Zirconium(IV) Using H-Point Standard Addition Method and Partial Least Squares

A new method for simultaneous kinetic-potentiometric determination of Zr(IV) and Fe(III) at trace levels using partial least-square (PLS) and H-point standard addition method (HPSAM) is described. The methods are based on the difference observed between complex reaction rate of Zr(IV) and Fe(III) with fluoride ion. Therefore, the reaction rate of Zr(IV) and Fe(III) with fluoride ion was monitored by a fluoride ion-selective electrode (FISE). Results have demonstrated that the simultaneous determination of Zr(IV) and Fe(III) can be done in the concentration ranges of 0.2 - 20.0 and 0.5 – 40.0 ?g mL-1, respectively. The total relative standard error of applying PLS method on 8 synthetic samples in the concentration ranges of 1.0 - 20.0 ?g mL-1 of Zr(IV) and 1.0 - 35.0 ?g mL-1 of Fe(III) was 1.85. The effects of certain foreign ions, upon the reaction rate, were determined for assessing the selectivity of the method. The proposed methods (HPSAM and PLS) were successfully applied to the simultaneous determination of Zr(IV) and Fe(III) in different water samples.