We then tested whether other metals would interfere with the quantification of palladium. In the presence of other metals at 345 nM, 30 nM palladium was detected fairly accurately, with the exception of silver ions (Figure and Figure ). The reason for the interference is currently unknown. Given the aforementioned reactivity of platinum, it was not surprising that the mixture of 30 nM palladium and 345 nM platinum generated stronger signal than 30 nM palladium alone. Therefore, in instances where both palladium-and platinum-catalyzed reactions are performed in the same synthetic sequence, it would be prudent that a more palladium-selective fluorometric method or a platinum-selective fluorometric method (manuscript in preparation) be employed. Also, if silver is suspected as a contaminant in large excess relative to palladium, ICP-MS analysis for silver ions may be necessary. Quantification. Synthetic samples prepared by palladium-catalyzed reactions may contain 10-2000 ppm palladium in the solid state. If 1 mg of a synthetic material as the solid is dissolved in 1 mL liquid, the resulting palladium concentrations will be 10-2000 ppb. In the metal analysis, if an aliquot (20 μL) is added to an assay solution (180 μL), the resulting mixture will contain 1-200 ppb (9.4-1880 nM) palladium.