Kinetic photometric determination of trace amounts of palladium (II) based on its catalytic effect on the reduction of safranin with hypophosphite

Abstract

A new kinetic method for the determination of trace amounts of palladium (II) based on its heterogeneous catalytic effect on the reduction reaction of safranin (SAF) by hypophosphite (HP) has been described. The reaction is monitored at 516 nm and the time elapsed, Δ<i>t,</i> for the absorbance to decrease by 1.5 absorbance units from its initial value is recorded (variable time method). The

influence of reaction variables such as safranin and hypophosphite

concentrations, ionic strength, and <i>p</i>H have been examined. The range of linearity is 0.03-2.22 ppm palladium(II) at temperature of 25°C (n=7, r=0.9998). The detection limit is 0.02 ppm. The relative standard deviation of the developed method is 1.8% (for 10 replicate determinations of 1.11 ppm of Pd(II)). The effect of interferences from other metal ions and some anions is also studied. The procedure has been applied successfully to the determination of Pd(II) in real samples.