Iron Isotopic Composition of Biological Standards Relevant to Medical and Biological Applications

Abstract

Iron isotopes are fractionated by multiple biological processes, which offers a novel opportunity to study iron homeostasis. The determination of Fe isotope composition in biological samples necessitates certified biological reference materials with known Fe isotopic signature in order to properly assess external reproducibility and data quality between laboratories. We report the most comprehensive study on the Fe isotopic composition for widely available international biological reference materials. They consist of different terrestrial and marine animal organs (bovine, porcine, tuna, and mussel) as well as apple leaves and human hair (ERC-CE464, NIST1515, ERM-DB001, ERM-BB186, ERM-BB184, ERM-CE196, BCR668, ERM-BB185, ERM-BB124). Previously measured Fe isotopic compositions were available for only two of these reference materials (ERC-CE464 tuna fish and ERM-BB186 pig kidney) and these literature data are in excellent agreement with our data. The Fe isotopic ratios are reported as the permil deviation of the 56Fe/54Fe ratio from the IRMM-014 standard. All reference materials present δ56Fe ranging from −2.27 to −0.35%0. Combined with existing data, our results suggest that animal models could provide useful analogues of the human body regarding the metabolic pathways affecting Fe isotopes, with many potential applications to medicine.

Iron, copper and zinc isotope compositions of biological reference materials determined by MC-ICP-MS

“…The δ 56 Fe and δ 65 Cu values of ERM-BB186 in this study are −2.07 ± 0.05‰ (2SD, N = 8), and 2.76 ± 0.06‰ (2SD, N = 7), respectively. These are consistent with the values reported by Rodushkin et al 40 ( δ 56 Fe = −2.07 ± 0.14‰ (2SD, N = 8), δ 65 Cu = 2.70 ± 0.25‰ (2SD, N = 8)) and Kubik et al 5 ( δ 56 Fe = −2.16 ± 0.09‰ (2SD, n = 6)) within uncertainty. As we discussed above, Zn isotopes are heterogeneous in ERM-BB186.…”

“…Fig. 6 d 56 Fe, d 65 Cu and d66 Zn values for biological reference materials reported in previous studies5,23,32,37,40,41,48,[52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67] and in this study (blue circles). Among published samples, some samples are sold out, which are represented by red hollow squares.…”

“…of Kubik et al 5 However, both whole soybean and skimmed soybean present lighter Fe isotope compositions than other plants, especially whole soybean, whose d 56 Fe value (−1.23 ± 0.06&, 2SD, N = 4) is even close to pig liver with d 56 Fe = −1.75 ± 0.02& (2SD, N = 3). This might be related to the mechanism of soybeans absorbing Fe.…”

“…Biological metabolism can cause signicant isotope fractionation of Fe, Cu, and Zn between the organs of plants and animals. 2,5 Therefore, Fe, Cu, and Zn isotope compositions are widely used in archaeology and paleontology. They can help reconstruct ancient food chains.…”

Longitudinal isotope ratio variations in human hair and nails

“…The δ 56 Fe value of -0.55 ± 0.05‰ (Table 2) for ERM-DB001 corresponds well with previously published value of -0.35 ± 0.24‰ (Kubik et al, 2021). The δ 56 Fe values for the CRMs NIES no.…”