RESUMO
An energy transfer technique for 4-(2-pyridylazo) resorcinol (PAR)-vanadium(V) and acridine orange (AO) was studied, and the optimum conditions of energy transfer system were also experimented. It was found that in citrate-Na2 HPO4 buffer solution at pH = 5.5, energy transfers from AO to vanadium(V)-PAR complexes. A new method based on energy transfer fluorescence quenching for the determination of trace vanadium(V) with AO-PAR-V(V) was established. The equation of linear regression is deltaF = 165.4c+2.5, and the determination range of vanadium is 0.012-0.5 microg x mL(-1), with detection limit of 0.004 5 microg x mL(-1). The correlation coefficient is R = 0.998 5, and relative standard deviation is 0.6%. The fluorescence reaction is completed within 15 minutes, and relative fluorescence intensity remains unchanged for 2.5 hours. The influence of foreign ions on the determination of V (0.5 microg x mL(-1)) was examined, with a related error of 5%. The method has been used in the determination of trace vanadium in biological samples with the relative error of 6.98%, which meets the requirements of trace analysis.
