Determination of Palladium by Spectrophotometry with 2-Tetrazolylazo-5-diethylamino Phenol

The conditions of colour reaction of a new reagent 2 _ tetrazolylazo _ 5 _ diethylamino phenol(TTZAPN)with Pd2+ are presented. The results show that the new colour reagent reacts with palladium to form a stable purple red complex(1∶2 by mole) in the medium of HAc-NaAc with pH 5.0. The apparent molar absorptivity is 4.51×104 L·mol-1·cm-1 and maximum absorption wavelength is at 530 nm. Beer's law is obeyed in the range of 0～1.0 mg/L for Pd2+. The method has been used for the direct determination of palladium in Pd _ containing catalyst and molecular sieve with satisfactory results.