Nonaqueous catalytic fluorometric trace determination of vanadium based onthe pyronine B-hydrogen peroxide reaction and flow injection after cloud point extraction

The catalytic effect of vanadium on the pyronine B-H2O2 system is examined. Enhancement of the catalytic reaction rate along with the efficiency and s electivity against vanadium is achieved in a formic acid environment in the presence of a nonionic surfactant (Triton X-114). Elimination of drastic i nterference caused by inorganic acids and aqueous matrix along with a 50-fo ld preconcentration of vanadium are facilitated through cloud point extract ion of its neutral complex with 8-quinolinol in an acidic solution. Subsequ ent flow injection analysis (FIA) with fluorometric detection renders the p roposed method ideal for selective and cost-effective determination of as l ittle as 0.020 mug L-1 vanadium in environmental, biological, and food subs trates. The preconcentration step can be applied simultaneously to multiple samples, allowing for massive preparation prior to analysis, compensating, thus, for the time-consuming procedure.