Simultaneous Laser Thermal Lens Spectrometric Determination of Trace Platinum and Palladium in an Aqueous Solution

Abstract A selective and sensitive method for determination of platinum and palladium (II) in an aqueous solution simultaneously by laser thermal lens spectrometry, based on the complex reaction of 2‐(3,5‐dichlopyridylazo)‐5‐dimethylaminoamiline (3,5‐di‐O‐PADMA) with platinum and palladium, has been developed. It is shown that the palladium complex can be formed at room temperature, while the platinum complex can be only formed after being heated in a boiling water bath. By using this difference of reaction temperature and the characteristic of the complexes mentioned above, the method for simultaneous determination of platinum and palladium was established in an aqueous solution without a pre‐separation. The results show that the dynamic linear ranges of determination for platinum and palladium are 0.005–0.04 μg/mL and 0.005–0.25 μg/mL respectively, and that the detection limits are both 0.002 μg/mL. The method has been applied to the determination of platinum and palladium simultaneously in alloy and catalyst samples with satisfactory results.