To target the 0-250 nM palladium range in the assay solutions with various amounts of palladium in mock APIs, we chose to subject 1.0 and 0.1 mg/mL mock API solutions to the reaction conditions. In a double-blinded manner, a member in our research group, who was not part of this study, prepared solutions of drugs spiked with known amounts of palladium. Four or five days after the samples were prepared, we analyzed these samples in three separate experiments. We used freshly diluted palladium solutions with known concentrations to create a calibration curve. The results are summarized in Table . In general, the method underestimated palladium concentrations, presumably because we compared four-to five-day old palladium solutions with freshly prepared palladium standard solutions. Nonetheless, the graph shown in Figure indicates that our method can determine the relative concentrations of palladium. actual [Pd] (ppm) in solid measured [Pd] (ppm)