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Abstract
The spectrophotometric methods for determination of vanadium in geological materials and some environmental samples using the 5-Br-PADAP and tungestophosphoric acid methods are described.
The proposed method using 5-Bromo-PADAP in presence of hydrogen peroxide in sulfuric acid medium is not only one of the most sensitive methods for determination of micro amount of V(V) but also is excellent in terms of selectivity and simplicity (R.S.D = 0.32 %). The alkali fusion dissolution method is chosen for the preparation of rock solutions because it minimizes and eliminates the interference effects from foreign ions in the examined samples specially from (Ti+4, Cr+6, Co+2, Ni+2, Cu+2, Mo+5, W+5, Zr+4 and Fe+3) ions. The developed method is reasonable to direct determination of V(V) in sample solution that will be useful in routine work for analysis.
The modified tungestophosphoric acid method is applied for estimation of vanadium in different rock samples beside some environmental samples (oil fly ashes) with good accuracy (R.S.D =1.87%). The procedure shows good reproducibility and accuracy for determination of vanadium in routine geochemical analysis. from the obtained results, one can deduce that the procedure is highly suited for using tungestophosphoric acid method in high vanadium concentrations than lower ones. Standard addition method can be used for determination of V(V) at low concentrations.
Finally, the two suggested methods can be applied for determination of vanadium in different matrices with good precision.