Catalytic kinetic spectrophotometric determination of trace amounts of silver in triton X-100 micellar medium

A catalytic method has been developed for the determination of trace amounts of Ag+ in Triton X-100 micellar medium. The method is based on the catalytic effect of silver(I) on the rate of a ligand substitution reaction between potassium ferrocyanide and 4,7-biphenyl-1,10-phenanthroline (BPT). The reaction was followed spectrophotometrically at 536 nm by measuring the induction period. Beer's law was obeyed in the range of 0-0.040 mug/mL Ag+ and the apparent molar absorptivity was 2.43 x 10(6) L mol(-1) cm(-1). Both the influence of reaction variables and the interference of coexistent ions were studied. The proposed method has been applied to the wastewater samples with satisfactory results. The recoveries were between 93.2 and 107% and the RSD was below 4.0%.