Determination of Platinum Group Metals in Catalysts by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) with Coprecipitation Separation and Enrichment

This study presents a method for determining platinum group metals (Pt, Pd, and Rh, PGMs for short) in metallic catalysts using inductively coupled plasma-atomic emission spectrometry (ICP-AES) with coprecipitation separation and enrichment. The monolithic catalysts were initially digested using ultrasonic-assisted HCl dissolution followed by Na2O2 melting and filtration of the residue, overcoming the challenge of uniform grinding catalyst samples. Subsequently, coprecipitation with polyethylene oxide (PEO) and Te was employed to mitigate interferences from Si and other elements. ICP-AES was then used for the determination of PGMs. In this method, co-existing elements, such as 200 mg<middle dot>L-1 of Te and 10 mg<middle dot>L-1 of Fe, Cr, Ni, Al, and Na, exhibit no interference in the quantification of PGMs. The limits of detection (3s) were 0.04, 0.016, and 0.014 mu g<middle dot>g-1 for Pt, Pd, and Rh, respectively. The limits of quantification (10s) were 0.13, 0.053, and 0.046 mu g<middle dot>g-1 for Pt, Pd, and Rh, respectively. The relative standard deviations (RSD, n = 7) ranged from 1.36% to 2.61% for Pt, 1.14% to 3.25% for Pd, and 1.89% to 3.78% for Rh, indicating the method's robustness and precision. Comparative analysis of the results obtained from six metallic catalyst products using this method and flame atomic absorption spectrometry (FAAS) reveals consistent results, further confirming the proposed method's reliability and feasibility for determining PGMs in metallic substrate catalysts.