Study on solid phase extraction and spectrophotometric determination of palladium with p-antipyrinylazo benzoic acid

A new reagent p-antipyrinylazo benzoic acid(AABA)was synthesized.Based on its color reaction with palladium(Ⅱ)and the solid phase extraction of its colored complex with C18 cartridge,a new method for the determination of palladium was studied.In the presence of OP and in HAc-NaAc buffer solution(pH3.5-5.5)medium,AABA reacts with palladium(Ⅱ)to form a stable 2∶1 complex.The colored complex extracted by C18 cartridge can be eluted with ethanol and is determined by spectrophotometry at 452 nm.Beer's law is obeyed in the range of 0.11.5 μg/mL for palladium and e=1.22×105 L·mol-1·cm1.The method was applied to determine the trace palladium in the Pt/Pd catalysts and the results found were agreement with those of AAS method.