Dual-Wavelength Spectral Correction Method for Simultaneous Determination of V(IV) and V(V)

Simultaneous determination of V(IV) and V(V) was performed when the calibration matrix was obtained using beta-corrected spectral data. The method is based on the reaction between V(IV) and V(V) and 4-(2-pyridylazo)-resorcinol (PAR) as a ligand at pH 6. Using β-correction technique true absorbance of chelate produced can be calculated because the quantity of absorbance, which has related to the fraction of reagent that reacted with metal ion and has been subtracted when reagent applied as reference by this correction has compensated. The parameters controlling behavior of the system were investigated and optimum conditions selected. Calibration model was constructed based on absorption spectra in the 540-600 nm range for 25 different mixtures of V(IV) and V(V) in the concentration ranges of 0.10-4.00 µgmL−1 of V(IV) and 0.10-5.00 µgmL−1of V(V). Applying this method to the analysis of mixtures of V(IV) and V(V) in waste water and soil samples with total relative standard error of less than 4.3% validated the proposed method.