Extractive spectrophotometric determination of vanadium by complexation of V(IlI) with <i>o</i>-phenanthroline and salicylic acid

200-201A simple spectrophotometric method for the determination of vanadium has been developed based on the reduction of pentavalent vanadium to V(III) and its complexation with o-phenanthroline and salicyclic acid. The coloured complex is extractable into dichloromethane. The method is free from the interference of a large number of metal ions, namely, Os(VIII), Re(VII), Mo(VI), Cr(VI), W(VI), U(VI), Ce(IV), Zr(IV), Cr(III), Al(III), Sb(III), Bi(III), Cu(II), Cd(II), Pb(II), Mg(II), Sr(I1), Ca(II), Zn(II), Ba(II), and Ag(I)