Selenium and its compounds – Determination of total selenium in urine by ICP-MS
Biomonitoring Method – Translation of the German version from 2023
Thomas Jäger1 (Method development)Philip Genser1 (Method development)
Peter Heitland2 (External verification)
Thomas Göen1 (Method development, 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 Hartwig3 (Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
MAK Commission4
1 Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute and Outpatient Clinic of Occupational, Social, and Environmental Medicine, Henkestraße 9–11, 91054 Erlangen, Germany
2 MVZ Medizinisches Labor Bremen GmbH, Haferwende 12, 28357 Bremen, Germany
3 Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany
4 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 Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area developed and verified the presented biomonitoring method.
Selenium is used in different industrial processes. In the workplace, employees are mainly exposed to elementary selenium and inorganic selenium compounds. In contrast, the non-occupationally exposed general population ingests mainly organic selenium compounds, like selenomethionine and selenocysteine, via the diet. Following exposure, selenium can be determined in serum/plasma and in whole blood/erythrocytes. While the selenium concentrations in these matrices reflect exposure from recent weeks or even months, urinary selenium concentrations are suitable for the determination of short-term exposure (e.g. of the last shift).
The aim of this work was to develop a selective method for the determination of total selenium in urine while avoiding the selenium enhancement effect caused by volatile selenium species (e.g. dimethyl selenide or dimethyl diselenide). The method has been comprehensively verified, and the reliability data have been confirmed by replication and verification of the procedure in a second, independent laboratory.
Urine samples are mineralised by microwave-assisted digestion using an acidic hydrogen peroxide-containing solution, thereby converting the various selenium species present in the urine into selenite. The selenium concentrations in the diluted digestion solutions are determined by mass spectrometry with inductively coupled plasma (ICP-MS) on
The microwave-assisted digestion allows for the accurate quantification of total selenium in urine even when volatile selenium species are present in the samples. The good precision and accuracy data show that the method provides reliable and accurate measurement values. The method is both selective and sensitive, and the quantitation limit of 0.5 μg/l urine is sufficient to determine occupational as well as background exposure to selenium and its compounds.
