An iron stable isotope comparison between human erythrocytes and plasma

von Blanckenburg, Friedhelm; Oelze, Marcus; Schmid, Dietmar G.; van Zuilen, Kirsten; Gschwind, Hans-Peter; Slade, Alan J.; Stitah, Sylvie; Kaufmann, Daniel; Swart, Piet (2014). An iron stable isotope comparison between human erythrocytes and plasma. Metallomics, 6(11), pp. 2052-2061. Royal Society of Chemistry 10.1039/C4MT00124A

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We present precise iron stable isotope ratios measured by multicollector-ICP mass spectrometry (MC-ICP-MS) of human red blood cells (erythrocytes) and blood plasma from 12 healthy male adults taken during a clinical study. The accurate determination of stable isotope ratios in plasma first required substantial method development work, as minor iron amounts in plasma had to be separated from a large organic matrix prior to mass-spectrometric analysis to avoid spectroscopic interferences and shifts in the mass spectrometer's mass-bias. The 56Fe/54Fe ratio in erythrocytes, expressed as permil difference from the “IRMM-014” iron reference standard (δ56/54Fe), ranges from −3.1‰ to −2.2‰, a range typical for male Caucasian adults. The individual subject erythrocyte iron isotope composition can be regarded as uniform over the 21 days investigated, as variations (±0.059 to ±0.15‰) are mostly within the analytical precision of reference materials. In plasma, δ56/54Fe values measured in two different laboratories range from −3.0‰ to −2.0‰, and are on average 0.24‰ higher than those in erythrocytes. However, this difference is barely resolvable within one standard deviation of the differences (0.22‰). Taking into account the possible contamination due to hemolysis (iron concentrations are only 0.4 to 2 ppm in plasma compared to approx. 480 ppm in erythrocytes), we model the pure plasma δ56/54Fe to be on average 0.4‰ higher than that in erythrocytes. Hence, the plasma iron isotope signature lies between that of the liver and that of erythrocytes. This difference can be explained by redox processes involved during cycling of iron between transferrin and ferritin.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences

UniBE Contributor:

van Zuilen, Kirsten

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

1756-5901

Publisher:

Royal Society of Chemistry

Language:

English

Submitter:

Sarah Antenen

Date Deposited:

07 Aug 2015 13:59

Last Modified:

15 Apr 2019 16:24

Publisher DOI:

10.1039/C4MT00124A

BORIS DOI:

10.7892/boris.70746

URI:

https://boris.unibe.ch/id/eprint/70746

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