Multi-collector ICP-mass spectrometry (MC-ICP-MS) was used for the isotopic analysis of Cu, Fe and Zn, isolated from human whole blood. For chromatographic isolation of these elements, the method first described by Marechal, Telouk and Albarede (Chem. Geol., 1999, 156, 251-273) and relying on the use of AG MP-1 strong anion exchange resin was further tailored and subsequently validated. It was shown that all three target elements could be obtained in pure form and with quantitative recovery from Seronorm whole blood reference material. MC-ICP-MS isotope ratio measurement conditions were optimized so as to avoid the influence of spectral overlap and the capabilities of several methods to correct for instrumental mass discrimination were compared. The method developed was then applied to a set of whole blood samples from supposedly healthy volunteers (reference population). For Fe, the by now well-known difference in isotopic composition between blood from male and female individuals was confirmed. The isotopic composition of Zn in whole blood was assessed to be governed by the diet as a significant difference could be established between blood from vegetarians and from omnivores, respectively. For the isotopic composition of Cu, interpretation of the results is more challenging, as neither gender, nor diet seems to have a significant influence, but the combined influence of both factors may show an effect

This paper presents a systematic evaluation of a commercially available strontium-specific extraction chromatographic resin based on a crown ether (Sr specÔ), for use in applications of Sr isotope ratio analysis dealing with samples displaying a complex and/or Ca-rich matrix composition. A protocol, consisting of (i) loading a sample digest in 7 M HNO 3 onto the resin, (ii) rinsing the resin with 7 M HNO 3 to remove concomitant matrix elements and (iii) rinsing the resin with 0.05 M HNO 3 to strip off the purified Sr fraction, was found to provide the best results. The performance in terms of (i) the purity of the Sr fraction obtained, (ii) the efficiency of Rb/Sr and Ca/Sr separation, (iii) the Sr recovery from samples with a complex and Ca-rich matrix composition and (iv) the Sr isotope ratios obtained using multi-collector ICP-MS, was evaluated for various amounts (250, 500, 750 and 2000 mL) of resin using digests of bone and soil certified reference materials, dental tissues, fluorite and glass samples. Further, it was investigated whether or not the isolation protocol introduces Sr isotopic fractionation. Also the possibility of regenerating the resin after use, allowing multiple use of the resin, was assessed. Finally, the Sr isotopic composition of 2 bone (NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal) and 2 soil (BCR CRM 141 Calcareous Loam Soil and BCR CRM 142 Light Sandy Soil) certified reference materials was determined. The method was shown to be fit-for-purpose for population migration studies and provenancing of archaeological artefacts, and is expected to be suited for a broad range of Sr isotope ratio applications.

In this work, the hypothesis of a possible dietary effect on the isotopic composition of Zn in blood from populations with different feeding habits, i.e. lacto-ovo vegetarians and omnivores, was investigated through isotopic analysis of Zn in common food products by multi-collector ICP - mass spectrometry (MC-ICP-MS). Several certified reference materials (CRMs) were also included in the sample set for comparison purposes. For these CRMs, the isotopic composition of Zn is expressed as δ-values, calculated with respect to both IRMM-3702 and JMC-ZnLyon, as isotopic standards. The range of δ(66)Zn values observed in food products was approximately 1.9‰. In general, vegetables, cereals and derived products showed an enrichment of the heavier Zn isotopes, whereas a depletion was observed in products of animal origin (meat, fish, egg and semi-skimmed milk), relative to human blood samples. Mussel, however, showed a significant enrichment of the heavier isotopes, which is hypothetically attributed to its accumulation behaviour. Thus, the lower δ(66)Zn values found in food products of animal origin appear to be reflected in the lower δ(66)Zn value observed in blood from an omnivorous population compared to that for a vegetarian population.

Since there is a significant difference in the isotopic composition of Cu and Fe in whole blood between men and women, it was hypothesized that menstruation and the associated Cu and Fe loss affect the isotopic composition of these metabolically relevant transition metals. To assess this hypothesis, whole blood from two groups of non-menstruating women was analyzed for its Cu, Fe and Zn isotopic composition using multi-collector ICP-mass spectrometry (MC-ICP-MS) and the results were compared to the values for a male and a female reference population. The first group of non-menstruating women consisted of women in their menopause, while the second group consisted of women that were not menstruating because of an intra-uterine device (IUD). Also the effect of age on the isotopic composition of Cu, Fe and Zn in whole blood was investigated. The Cu and Fe isotopic composition of whole blood indeed seems to be influenced by menstruation. Non-menstruating women show an isotopic signature indistinguishable from that of the male reference population. The results for both groups of non-menstruating women do not differ significantly from one another and there does not seem to be an "age effect" for these two elements. Also for the isotopic composition of Zn in whole blood, no age effect could be demonstrated. No influence of menstruation was found either. However, a significant difference in the Zn isotopic composition was found between women in their menopause and women with an IUD. Possibly, this can be explained by a hormonal effect on the isotopic signature of Zn

As the iron status of an individual cannot be adequately assessed on the basis of the (total) Fe concentration in whole blood or serum, in medicine a number of parameters, such as the serum concentrations of ferritin, transferrin and soluble transferrin receptor and the transferrin saturation, are routinely determined instead. As previous research has shown that also the isotopic composition of Fe in blood and tissues is dependent on the metabolism, the present study assessed whether Fe isotopic composition in whole blood provides information as to an individual's iron status. Fe isotopic analysis of whole blood samples from a reference population (healthy volunteers) was carried out using multi-collector ICP-mass spectrometry (after chromatographic target element isolation) and the results obtained were investigated by statistical means as to their potential relation with the iron status parameters conventionally used in medicine. A low δ(56)Fe value was demonstrated to coincide with high iron status and a high δ(56)Fe value with low iron status, thus reflecting the response of the body to this iron status in terms of iron uptake, distribution between blood and stores and mobilization of storage iron. In a second phase, the iron isotopic composition in blood from patients treated for hemochromatosis type I and from patients with anemia of chronic disease (ACD) was determined. The results for hemochromatosis patients plotted with the values of low iron status, while those for ACD patients plotted with the values of high iron status. By taking a closer look at the aberrant iron metabolism that comes with these diseases, it can be seen that the patient samples confirm the conclusions drawn for the reference population. Patients with hemochromatosis type I have a strongly upregulated iron uptake, like healthy individuals with low iron status. The metabolism of patients suffering from ACD tries to remove iron from the circulation by downregulating the iron uptake, moving more absorbed iron to the stores and by not using any iron from these storage sites, which is in agreement with the responses of the human body to high iron status. This suggests that the conclusions made for healthy individuals are extendable to patients with aberrant iron metabolism.