Enhancement of a Catalysis-Based Fluorometric Detection Method for Palladium through Rational Fine-Tuning of the Palladium Species

Abstract

Metal analyses in chemistry, materials science, and environmental science are currently performed using techniques such as inductively coupled plasma mass spectrometry and X-ray fluorescence, which require expensive instrumentation and are not high-throughput. Although fluorescent probes are known for their sensitivity and specificity and are amenable to high-throughput analyses, the robustness of such analyses are typically limited due to their binding-based nature. Herein we report an improvement of our previously reported catalysis-based fluorescent probe for palladium by rationally fine-tuning the redox and coordination chemistries of the palladium species involved in the O-deallylation reaction. This method now rivals current analytical methods with respect to sensitivity. We demonstrate palladium detection in various active pharmaceutical ingredients, spent catalytic converter materials, and a metal scavenger resin. Thus, fluorescent methods may have the potential for substituting the current instrument-intensive techniques.

Systematic Investigation of Photoinduced Electron Transfer Controlled by Internal Charge Transfer and Its Consequences for Selective PdCl2 Coordination

“…[1] Particularly for the synthesis of drugs, palladium-catalyzed reactions are widely used, [2] but after purification residual palladium contaminates the final product at a much higher level (typically 300-2000 ppm) [3] than the specified threshold in drugs (5-10 ppm). [4] The proposed maximum dietary intake of palladium is less than 1.5-15 mg per person per day, [4] as palladium may be a health hazard.…”

Studies Toward an Ideal Fluorescence Method to Measure Palladium in Functionalized Organic Molecules: Effects of Sodium Borohydride, Temperature, Phosphine Ligand, and Phosphate Ions on Kinetics

“…[18] In that study, we arbitrarily chose [API] = 1.25 mg mL À1 for the palladium detection reactions. Considering the complex dynamics of palladium species, we deemed it critical to determine the range of API concentrations in which the fluorescence method for palladium quantification would be reasonably accurate.…”

“…The rate of the deallylation of 1 under the reaction conditions was found to be in the first order with respect to the concentration of palladium. [18] At lower API concentrations, the equilibrium between Pd…”

“…3 Both acidic and basic functional groups were compatible with the method in the phosphate buffer (pH 7) unlike the 2009 version. [18] …”

A 4‐Amino‐1,8‐Naphthalimide Derivative for Selective Fluorescent Detection of Palladium(II) Ions

“…Palladium-catalyzed reactions are highly effective for the synthesis of complex molecules, including many kinds of drugs. [3] However, the residual Pd level in products of chemical synthesis is often higher than the permissible threshold. This metal ion can bind to DNA, protein, and other biomolecules and disturbs biological processes, thus, it is a poison and a hazard.…”