We describe a chemical separation protocol of calcium from biological materials for isotopic measurement by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). The method was tested using elution profiles along with HCl and HNO 3 acids only, on human urine, sheep serum and red blood cells (RBC), seawater and herbaceous plants. It allows the elimination of all interfering species (including K, Sr, Mg) and the remaining matrix (including Fe, P, Na and S) beyond required levels. In order to further test this protocol and better understand the Ca isotopic signatures of mammalian fluids and organs, we purified and analyzed a wide range of materials from sheep, i.e. serum, RBC, muscle, liver, kidneys, enamel, bone, urine and feces. The data show a wide range of variations, expressed as d, over 1& per amu, with a precision of 0.1& or better, spanning most of the variability reported so far. Red blood cells appeared to be heavier than serum by 0.3& per amu. This isotopic difference between serum and red blood cells was not taken into account in previous studies and it provides further information on Ca isotopic cycling in organisms. The Ca isotopic compositions of organs are correlated with concentrations, bone and RBC representing the two end-members, bone being Ca rich and 44 Cadepleted and RBC Ca poor and 44 Ca-enriched. The trend is compatible with a distillation process by which Ca is extruded from cells along with a kinetic fractionation process favoring lighter Ca isotopes. Material and methods SamplesChemical purication of Ca was tested on seawater, freeze-dried human urine, sheep serum and red blood cells (RBC) and herbaceous plants. Seawater, SRM915b, bone meal NIST SRM1486, cave bear and two sheep enamel samples (CBE, E1634, E9646 respectively) were chosen to assess precision and

High quality records of stratospheric volcanic eruptions, required to model past climate variability, have been constructed by identifying synchronous (bipolar) volcanic sulfate horizons in Greenland and Antarctic ice cores. Here we present a new 2600-year chronology of stratospheric volcanic events using an independent approach that relies on isotopic signatures (Δ33S and in some cases Δ17O) of ice core sulfate from five closely-located ice cores from Dome C, Antarctica. The Dome C stratospheric reconstruction provides independent validation of prior reconstructions. The isotopic approach documents several high-latitude stratospheric events that are not bipolar, but climatically-relevant, and diverges deeper in the record revealing tropospheric signals for some previously assigned bipolar events. Our record also displays a collapse of the Δ17O anomaly of sulfate for the largest volcanic eruptions, showing a further change in atmospheric chemistry induced by large emissions. Thus, the refinement added by considering both isotopic and bipolar correlation methods provides additional levels of insight for climate-volcano connections and improves ice core volcanic reconstructions.

Estimating global fluxes of precious metals is key to understanding early monetary systems. This work adds silver (Ag) to the metals (Pb and Cu) used so far to trace the provenance of coinage through variations in isotopic abundances. Silver, copper, and lead isotopes were measured in 91 coins from the East Mediterranean Antiquity and Roman world, medieval western Europe, 16th-18th century Spain, Mexico, and the Andes and show a great potential for provenance studies. Pre-1492 European silver can be distinguished from Mexican and Andean metal. European silver dominated Spanish coinage until Philip III, but had, 80 y later after the reign of Philip V, been flushed from the monetary mass and replaced by Mexican silver.A particularly momentous time during the early history of modern European economy was the attempt by Hamilton (1) to demonstrate that the great Price Revolution (1520-1650) was largely fueled by the influx of American silver rather than by widespread coinage debasement and minting of the lowdenomination copper "vellón". The idea connecting silver influx to European inflation was actually proposed as far back as the16th century by the French philosopher Jean Bodin (2) and is commonplace in classical economics. Huge amounts of silver, ∼300 t annually (3-5), were mined in the Spanish Americas from the 16th to the 18th centuries. That much silver could not be absorbed locally by the American economy and therefore headed for the European market through major Spanish harbors (6), notably Seville (7), and to the Far East either directly through the Philippines or indirectly through Europe (8). The thesis that the Price Revolution in Spain was fueled by the influx of American silver has, however, become controversial in recent literature (9-11). More specifically, some authors emphasized that the arrival of American metals (ca. 1550 to ca. 1809) does not coincide with the period of inflation (ca. 1520 to ca. 1650) (9-11). Understanding silver monetary mass and circulation relies on three types of primary data: (i) the register of taxes collected when the silver bars received the royal stamp (the Quinto in Peru and the Diezmo in Mexico) (12, 13), (ii) the register of the European harbors used to import the silver shippings (1), and (iii) the compilation of contemporaneous gazettes (9). These data are imprecise or even incomplete, especially for trade registers between 1660 and 1809 (9), and do not take contraband and piracy silver into account (8,(14)(15)(16)(17). In addition, any memory of the origin of the metal is lost by recoinage, whenever silver is exported or a new king comes to power, or upon debasement. Reliable tracers of the monetary mass and exchange that can see through the destructive alterations of coinage silver therefore are needed. Over the last 30 years, lead isotope compositions of metallic ores have been collected and gathered into large databases and broadly used as a tool for provenance studies of archaeological artifacts (18)(19)(20). The main factors of provenance analysis are (i) the...

The notion of a dry Moon has recently been challenged by the discovery of high water contents in lunar apatites and in melt inclusions within olivine crystals from two pyroclastic glasses. The highest and most compelling water contents were found in pyroclastic glasses that are not very common on the lunar surface. To obtain more representative constraints on the volatile content of the lunar interior, we measured the Zn content, a moderately volatile element, of mineral and rock fragments in lunar soils collected during Apollo missions. We here confirm that the Moon is significantly more depleted in Zn than the Earth. Combining Zn with existing K and Rb data on similar rocks allows us to anchor a new volatility scale based on the bond energy of nonsiderophile elements in their condensed phases. Extrapolating the volatility curve to H shows that the bulk of the lunar interior must be dry (≤1 ppm). This contrasts with the water content of the mantle sources of pyroclastic glasses, inferred to contain up to approximately 40 ppm water based on H2O/Ce ratios. These observations are best reconciled if the pyroclastic glasses derive from localized water‐rich heterogeneities in a dominantly dry lunar interior. We argue that, although late addition of 0.015% of a chondritic veneer to the Moon seems required to explain the abundance of platinum group elements (Day et al. 2007), the volatile content of the added material was clearly heterogeneous.

This review examines recent applications of stable copper, zinc and sulfur isotopes to medical cases and notably cancer. The distribution of the natural stable isotopes of a particular element among coexisting molecular species varies as a function of the bond strength, the ionic charge, and the coordination, and it also changes with kinetics. Ab initio calculations show that compounds in which a metal binds to oxygen- (sulfate, phosphate, lactate) and nitrogen-bearing moieties (histidine) favor heavy isotopes, whereas bonds with sulfur (cysteine, methionine) favor light isotopes. Oxidized cations (e.g., Cu(ii)) and low coordination numbers are expected to favor heavy isotopes relative to their reduced counterparts (Cu(i)) and high coordination numbers. Here we discuss the first observations of Cu, Zn, and S isotopic variations, three elements closely related along multiple biological pathways, with emphasis on serum samples of healthy volunteers and of cancer patients. It was found that heavy isotopes of Zn and to an even greater extent Cu are enriched in erythrocytes relative to serum, while the difference is small for sulfur. Isotopic variations related to age and sex are relatively small. The Cu/Cu ratio in the serum of patients with colon, breast, and liver cancer is conspicuously low relative to healthy subjects. The characteristic time over which Cu isotopes may change with disease progression (a few weeks) is consistent with both the turnover time of the element and albumin half-life. A parallel effect on sulfur isotopes is detected in a few un-medicated patients. Copper in liver tumor tissue is isotopically heavy. In contrast, Zn in breast cancer tumors is isotopically lighter than in healthy breast tissue. Zn/Zn is very similar in the serum of cancer patients and in controls. Possible reasons for Cu isotope variations may be related to the cytosolic storage of Cu lactate (Warburg effect), release of intracellular copper from cysteine clusters (metallothionein), or the hepatocellular and biosynthetic dysfunction of the liver. We suggest that Cu isotope metallomics will help evaluate the homeostasis of this element during patient treatment, notably by chelates and blockers of Cu trafficking, and understand the many biochemical pathways in which this element is essential.

Sulfate aerosol (SO 4 2− ) preserved in Antarctic ice cores is discussed in the light of interactions between marine biological activity and climate since it is mainly sourced from biogenic emissions from the surface ocean and scatters solar radiation during traveling in the atmosphere. However, there has been a paradox between the ice core record and the marine sediment record; the former shows constant non-sea-salt (nss-) SO 4 2− flux throughout the glacial-interglacial changes, and the latter shows a decrease in biogenic productivity during glacial periods compared to interglacial periods. Here, by ensuring the homogeneity of sulfur isotopic compositions of atmospheric nss-SO 4 2− (δ 34 S nss ) over East Antarctica, we established the applicability of the signature as a robust tool for distinguishing marine biogenic and nonmarine biogenic SO 4 2− . Our findings, in conjunction with existing records of nss-SO 4 2− flux and δ 34 S nss in Antarctic ice cores, provide an estimate of the relative importance of marine biogenic SO 4 2− during the last glacial period to be 48 ± 10% of nss-SO 4 2− , slightly lower than 59 ± 11% during the interglacial periods. Thus, our results tend to reconcile the ice core and sediment records, with both suggesting the decrease in marine productivity around Southern Ocean under the cold climate.

A new technique allows the precise measurement of sulfur isotopes by MC-ICP-MS in a large number of small biological samples.

Despite widespread applications of sulfur isotope mass-independent fractionation (MIF) signals for probing terrestrial and extra-terrestrial environments, there has been no international sulfur isotope reference material available for normalization of D 33 S and D 36 S data. International reference materials to anchor isotope values are useful for interlaboratory data comparisons and are needed to evaluate, e.g., whether issues exist associated with blanks and mass spectrometry when using different analytical approaches.We synthesized two sodium sulfate samples enriched in 33 S with different magnitudes, and termed them S-MIF-1 and S-MIF-2, respectively. The sulfur isotopic compositions of these two samples were measured in five different laboratories using two distinct techniques to place them on the V-CDT scale for d 34 S and a provisional V-CDT scale for D 33 S and D 36 S. We obtained average d 34 S values of S-MIF-1 ¼ 10.26 AE 0.22& and S-MIF-2 ¼ 21.53 AE 0.26& (1s, versus V-CDT). The average D 33 S and D 36 S values of S-MIF-1 were determined to be 9.54 AE 0.09& and À0.11 AE 0.25&, respectively, while the average D 33 S and D 36 S values of S-MIF-2 are 11.39 AE 0.08& and À0.33 AE 0.13& (1s, versus V-CDT). The lack of variation among the interlaboratory isotopic values suggests sufficient homogeneity of S-MIF-1 and S-MIF-2, especially for D 33 S. Although additional measurements may be needed to ensure the accuracy of the isotopic compositions of S-MIF-1 and S-MIF-2, they can serve as working standards for routine D 33 S analysis to improve data consistency, and have the potential to serve as secondary sulfur isotope reference materials to address issues such as scale contraction/expansion and for normalization and reporting of D 33 S and D 36 S between laboratories. For the same reasons as listed for sulfur isotopes, the same standards were also artificially enriched in 17 O. The calibration is still in progress but first estimations gave D 17 O ¼ 3.3 AE 0.3& with unassigned d 18 O.