Rigorous and iterative purification and analytical processes are necessary to ensure the absence of toxic metals such as palladium in active pharmaceutical ingredients to comply with federal regulations. Palladium catalysis is also used to synthesize organic polymers, including photovoltaic materials, which causes metal contamination that can negatively impact the materials’ performance. Traditionally, trace palladium is quantified using either inductively coupled-plasma mass spectrometry (ICP-MS) or inductively coupled-plasma optical emission spectroscopy (ICP-OES), which are sensitive and robust but expensive, slow, and usually unavailable at production sites. A significant drawback of these methods is a multi-week delay, including sample shipping times, to quantify trace metals. Presented is a method of measuring metals on-site with simple procedures and instruments using a colorimetric method that makes use of a chemosensor that rapidly, reversibly, and autonomously stalls, allowing the user to stop, start, and reverse the reaction, with the ability to detect palladium in concentrations as low as 0.1 ppb.
Nieberding, M., Tracey, M. P., & Koide, K. (2017). Noneffervescent Method for Catalysis-Based Palladium Detection with Color or Fluorescence. ACS Sensors, 2(11), 1737–1743. https://doi.org/10.1021/acssensors.7b00697
Tracey, M. P., Pham, D., & Koide, K. (2015). Fluorometric imaging methods for palladium and platinum and the use of palladium for imaging biomolecules. Chemical Society Reviews, 44(14), 4769–4791. https://doi.org/10.1039/c4cs00323c
Lukomski, L., Pohorilets, I., & Koide, K. (2019). Third-Generation Method for High-Throughput Quantification of Trace Palladium by Color or Fluorescence. Organic Process Research & Development, 24(1), 85–95. https://doi.org/10.1021/acs.oprd.9b00472
Koide, K., Tracey, M., Bu, X. et al. A competitive and reversible deactivation approach to catalysis-based quantitative assays. Nat Commun 7, 10691 (2016). https://doi.org/10.1038/ncomms10691