A SPECTROPHOTOMETRIC METHOD FOR VANADIUM DETERMINATION IN SEVERAL GEOLOGICAL MATRICES USING ALIZARIN RED S

A simple versatile developed spectrophotometric method for the determination of vanadium (V) in several geological matrices was suggested and studied in the present work, using alizarin red S as a chromogenic dye. Several factors were studied for optimum determination, namely; effect of pH, buffer solution, dye concentration, sequence of addition, duration time and molar ratio. The complex was stable for two hours. Beer’s law was obeyed in the concentration range 0.05-6 μg ml-1 at λmax 483 nm with molar absorptivity (ε) value 0.72x104 L mol-1 cm-1, percentage relative standard deviation (%RSD) (4.5% ) and % error (1.97%). Tolerance limits of foreign cations and anions were studied. A precipitation method for separation of the concomitant interfering ions was applied to overcome the interference effect of these elements with vanadium, to ease its determination with accurate and precise values. The proposed method was successfully applied to analysis of vanadium in different rock types.