Chemometrics-assisted kinetic-potentiometric methods for simultaneous determination of Fe(II), Al(III), and Zr(IV)...

Partial least-squares (PLS) and principal component regression (PCR) were used for the simple, accurate, and simultaneous determination of Fe(III), Al(III), and Zr(IV) using the kinetic data from a novel potentiometric method. The complex forming reaction rate of Fe(III), Al(III), and Zr(IV) with fluoride ions was monitored by a fluoride ion-selective electrode. The experimental data showed the good ability of ion-selective electrodes as detectors, not only for the direct determination of fluoride ion, but also for simultaneous kinetic-potentiometric analysis using the PLS and PCR methods. The methods are based on the differences observed in the complexation rate of fluoride ions. Results have demonstrated that the simultaneous determination of Fe(III), Al(III), and Zr(IV) can be performed in concentration ranges of 0.5-18.5, 0.2-14.0, and 0.4-21.0 microg/mL, respectively. After the application of PLS, the total root mean square error of prediction (RMSEP) was found to be 0.121, 0.122, and 0.129 for the 10-sample experiment of Fe(III), Al(III), and Zr(IV), respectively. For PCR, the RMSEP was found to be 0.156, 0.162, and 0.178 for the 10-sample experiment of Fe(III), Al(III), and Zr(IV), respectively. The effects of certain foreign ions upon the reaction rate were determined for assessing the selectivity of the method. The proposed methods (H-point standard addition, PLS, and PCR) were evaluated using a set of synthetic sample mixtures, and applied for the simultaneous determination of Fe(III), Al(III), and Zr(IV) in water samples.