Abstract
The current study involved the evaluation of five different internal standards (Sc, Co, Y, In and La) as well as normal external or direct calibration methods in the simultaneous quantification of all six platinum group metals (PGMs) and gold (precious metals). The use of Sc as internal standard in the quantitative determination of precious metals in a liquid reference material (RM) and the geological Pyroxenite CRM was shown to yield excellent recoveries (> 99%) compared to the other metals used as internal standard in this study and the direct calibration method (> 91 %).Os recovered only 89% of the expected metal content. The evaluation of different proposed models (wavelength combinations, ionization and/or excitation energy) did not succeed in identifying or discriminating between the unsuccessful and successful internal standards. The robustness of the Sc internal standard addition method was evaluated with the variation in solution matrix (addition of HCl and NaCl). The analytical method (total metal recovery) proved to be very sensitive to elevated unmatched HCl matrix levels (above 1.0 mL of HCl (32% v/v) added) and Na+ addition larger than 4 ppm sodium using ICP-OES. KEY WORDS: Internal standard, Scandium, Precious metals, Spectrometric techniques, ICP-OES Bull. Chem. Soc. Ethiop. 2016, 30(1), 55-70.DOI: http://dx.doi.org/10.4314/bcse.v30i1.5
Highlights
Precious metals, in particular the platinum group metals (PGMs), i.e. Pt, Rh, Ru, Ir, Pd and Os, are extremely useful and important elements in modern life
Other problems associated with precious metal quantification includes volatility and instability of some of the products, lack of certified reference materials (CRMs) and interference caused by ionized elements (EIEs)
Yttrium is highly recommended by the International Organization for Standardization (ISO) in the determination of PGMs from re-cycled materials and was considered [8]
Summary
In particular the platinum group metals (PGMs), i.e. Pt, Rh, Ru, Ir, Pd and Os, are extremely useful and important elements in modern life. These metals are used to reduce pollution, for energy applications, as well as construction of catalysts for the production of large-scale industrial chemicals. The concentrations of precious metals in a typical ore vary significantly with Pt and Pd, which are 5 to 10 times higher than Rh and Ru and around 50 times higher than Os and Ir [3] The separation of this group as well as the quantification of the individual elements is further complicated by very similar chemical and physical properties. Other problems associated with precious metal quantification includes volatility and instability of some of the products (mainly Os and Ru), lack of certified reference materials (CRMs) and interference caused by ionized elements (EIEs)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
