Catalytic Spectrophotometry Determination of Ultratrace Amounts of Silver with Solubilizing Effect of Nonionic Surfactant

The synthesis and analytical properties of 4,4′-bis(antipyrinyl-4-diazoamino) biphenyl (BAPDAB) were described for the first time. A catalytic kinetic method for the determination of silver was proposed. In the presence of Triton X-100 as a solubilizing agent and 2,2′-dipyridyl as an activator, silver has a very strong catalytic effect on oxidative decoloration of BAPDAB by persulfate in acetic add medium. The reaction was followed spectrophotometrically by measuring the decrease of absorbance of BAPDAB at 478 nm and 50 °C. The calibration graphs are of good linearity in the range of 8.0 × 10−10–1.0 × 10−6 mol/L by a fixed time method. The limit of detection is down to 5.0 × 10−10 mol/L. The catalytic reaction is pseudo-first-order with respect to silver, which in real samples was determined with satisfactory results.