Precious metals – Determination of gold, silver, platinum, rhodium, and iridium in urine by ICP-SF-MS or ICP-Q-MS

Biomonitoring Method – Translation of the German version from 2024

Bernhard Michalke¹ (Method development)
Katharina Blümlein² (External verification)
Thorben Schirmer² (External verification)
Petra Krystek³ (External verification)
Robin de Kruijff³ (External verification)
Esther Spruit³ (External verification)
Mehmet Sarilar³ (External verification)
  Thomas Göen⁴ (Head of the working group “Analyses in Biological Materials” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
  Andrea Hartwig⁵ (Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
  MAK Commission<sup>6

1</sup> Helmholtz Zentrum München, Environmental Health Center, Research Unit Analytical BioGeoChemistry, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
² Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM), Bio- and Environmental Analytics, Nikolai-Fuchs-Straße 1, 30625 Hannover, Germany
³ Delft University of Technology (TU Delft), Reactor Institute, Mekelweg 15, 2629 JB Delft, The Netherlands
⁴ Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute and Outpatient Clinic of Occupational, Social, and Environmental Medicine, Henkestraße 9–11, 91054 Erlangen, Germany
⁵ Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany
⁶ Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Germany

Abstract

The working group “Analyses in Biological Materials” of the German Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) developed and verified the presented biomonitoring method for the determination of urinary concentrations of gold, silver, platinum, rhodium, and iridium using high-resolution inductively coupled plasma–sector-field mass spectrometry (ICP‑SF‑MS) or inductively coupled plasma‑single quadrupole mass spectrometry (ICP‑Q‑MS). The aim of this work was to establish a reliable, selective and sensitive method which is suitable for routine analysis in laboratories with high sample throughput. The method is characterised by diluting the urine samples 1 ∶ 5 (v/v) with 10% aqua regia, addition of terbium as internal standard, and determination of the concentrations of the respective precious metals by ICP‑SF‑MS or ICP‑Q‑MS. The procedure has been comprehensively validated by ICP‑SF‑MS, and the reliability data have been confirmed by replication and verification of the procedure in a second, independent laboratory using ICP‑Q‑MS. Quantitative evaluation is carried out via external calibration using precious-metal standards diluted with 10% aqua regia. The good precision and accuracy data show that the method provides reliable and accurate analytical results. The method is both selective and sensitive, and the limits of quantitation of 12.3–18.5 ng/l urine (ICP‑SF‑MS) or of 12.5 ng/l urine (ICP‑Q‑MS) are sufficient to determine occupational exposure to gold, silver, platinum, rhodium, and iridium and, in single cases, also exposure in the general population.

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