Spectrophotometric determination of vanadium(V) as a mixed thiocyanate-4-pyridone complex

Abstract

The spectrophotometric determination of vanadium(V) as a mixed thiocyanate-3-hydroxy-2-methyl-1-phenyl-4-pyridone (HX) complex and as a mixed thiocyanate-3-hydroxy-2-methyl-1-(4-tolyl)-4-pyridone (HY) complex is described. The extracted complexes in chloroform have a maximum absorbance at 450 and 650 nm. The optimal conditions for the extraction and spectrophotometric determination of vanadium(V) are determined. The solutions of the V-SCN-HX and V-SCN-HY complexes in chloroform obey Beer's law in the range 1–10 ppm of vanadium, and are stable for at least 24 hr. The molar absorptivity of the method is 6.8 × 10 3 liters mol −1 cm −1. The molar ratio V:SCN:HX (HY) of the extracted complex is 1:1:2.