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Bodily variability of zinc natural isotope abundances in sheep
Author(s) -
Balter Vincent,
Zazzo Antoine,
Moloney Aidan P.,
Moynier Fred,
Schmidt Olaf,
Monahan Frank J.,
Albarède Francis
Publication year - 2010
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4425
Subject(s) - chemistry , zinc , isotope , environmental chemistry , natural (archaeology) , isotopes of zinc , natural abundance , stable isotope ratio , radiochemistry , mass spectrometry , chromatography , organic chemistry , nuclear physics , paleontology , geology , physics
Evidence is growing that the range of zinc stable isotope compositions, represented by the deviation of 66 Zn in permil units relative to a standard and expressed as δ 66 Zn, is larger in organic matter than in inorganic material. This study reports the variations of δ 66 Zn in various organs of sheep raised on a controlled diet. Zinc was purified by anion‐exchange chromatography. The Zn concentrations and Zn stable isotope compositions were determined by quadrupole inductively coupled plasma mass spectrometry and multi‐collector inductively coupled plasma mass spectrometry, respectively. The data show that δ 66 Zn variability exceeds 1‰, with bone, muscle, serum and urine enriched in the heavy isotopes, and feces, red blood cells, kidney and liver enriched in light isotopes, all relative to the diet value. The 66 Zn enrichment of the circulating serum reservoir is likely to take place in the digestive tract, probably through the preferential binding of lighter isotopes with phytic acid, which is known to control the uptake of metallic elements. Mass balance calculations suggest that the 66 Zn depletion between diet and feces, which is not balanced by any other outward flux, leads to a secular isotopic drift in serum. A simple time‐dependent two‐box model, involving the gastro‐intestinal tract on the one hand and the muscle and bone on the other, predicts that the maximum 66 Zn enrichment, which equals the difference in δ 66 Zn between diet and bulk (∼0.25‰), is reached after about ten years. Therefore, a better understanding of the variations of natural abundance of Zn isotopes in animals and humans will probably bring new perspectives for the assessment of their Zn status. Copyright © 2010 John Wiley & Sons, Ltd.