Recent developments and trends in the application of strontium and its isotopes in biological related fields

Analytical strategies for sensitive and precise determination of 87Sr/86Sr in olive oil through ion extraction, chromatographic separation, and multicollector inductively-coupled plasma mass-spectrometry

Several food regulatory bodies regard olive oil as highly susceptible to food fraud, largely due to its substantial economic worth. Precise analytical tools are being developed to uncover these types of fraud. This study examines an innovative approach to extract strontium (Sr) from the olive oil matrix (via EDTA complexation and ion-exchange chromatography) and to determine its isotope composition by MC-ICP-MS. This technique was compared to a commonly used technique (i.e. acid extraction and extraction chromatography), and then validated. Three olive oils that are sold in France were prepared and analyzed by two methods: 1) acid extraction prior to Sr purification by Sr-spec resin and 2) complexation by EDTA prior to Sr purification by AG50W-X8. These methods were applied for the determination of the 87Sr/86Sr isotope ratio of 23 olive oils from various countries. We also demonstrated the feasibility of the method for the detection of olive oil mixtures.

Signature of Sr isotope ratios and the contents of elements as a tool to distinguish wine regions in China

This study investigated 120 Chinese wines from seven regions and had two objectives: to clarify the Sr isotope ratios and elemental characteristics of each region and to develop a strategy to distinguish the geographic origin of wine without authentic samples to predict its origin. The analyzed 87Sr/86Sr values ranged from 0.708256 to 0.715148, which correlated with the geological characteristics of the regions where they were grown. The Hexi Corridor exhibited the highest ratios of Sr isotopes, while Xinjiang had the lowest. The 87Sr/86Sr values were applied to establish a prediction map which was evaluated through cross-validation. The prediction error was found to be less than 0.00074. The Sr isotope ratio could remain stable for an extended period in a specific location. This map shows the feasibility of identifying wine origin and could be applied to other food products. Adding Sr isotope ratios could improve the accuracy in tracing wine origin.

Investigating strontium isotope linkage between biominerals (uroliths), drinking water and environmental matrices

This study presents the mineralogy and strontium isotope ratio (87Sr/86Sr) of 21 pathological biominerals (bladder and kidney stones) collected from patients admitted between 2018 and 2020 at the Department of Urology of the San Pio Hospital (Benevento, southern Italy). Urinary stones belong to the calcium oxalate, purine or calcium phosphate mineralogy types. Their corresponding 87Sr/86Sr range from 0.707607 for an uricite sample to 0.709970 for a weddellite one, and seem to be partly discriminated based on the mineralogy. The comparison with the isotope characteristics of 38 representative Italian bottled and tap drinking waters show a general overlap in 87Sr/86Sr with the biominerals. However, on a smaller geographic area (Campania Region), we observe small 87Sr/86Sr differences between the biominerals and local waters. This may be explained by external Sr inputs for example from agriculture practices, inhaled aerosols (i.e., particulate matter), animal manure and sewage, non-regional foods. Nevertheless, biominerals of patients that stated to drink and eat local water/wines and foods every day exhibited a narrower 87Sr/86Sr range roughly matching the typical isotope ratios of local geological materials and waters, as well as those of archaeological biominerals from the same area. Finally, we conclude that the strontium isotope signature of urinary stones may reflect that of the environmental matrices surrounding patients, but future investigations are recommended to ultimately establish the potential for pathological biominerals as reliable biomonitoring proxies, taking into the account the contribution of the external sources of Sr.

Stable Isotope Provenance of Unidentified Deceased Migrants-A Pilot Study

In the global migration crisis, one of the challenges in the effort to identify deceased migrants is establishing their region of origin, which facilitates the search for ante mortem data to be compared with the post mortem information. This pilot study explores the potential of using stable isotope analysis to distinguish between individuals coming from West Africa and the Horn of Africa. Six individuals (four of known origin and two of unknown origin) were sampled. δ13CVPDB(keratin), δ15NVPDB(keratin) and δ18OVSMOW(keratin) of hair were analysed using Elemental Analyzers coupled with Isotope Ratio Mass Spectrometry (IRMS). δ18OVSMOW(carbonate) and δ13CVPDB(carbonate) of bone were analysed using GasBench II with IRMS, while 87Sr/86Sr composition was determined in bone and dental enamel using laser ablation multi-collector inductively coupled plasma mass spectrometry. The stable isotope compositions of the individual from the Horn of Africa differed from the other individuals. The differences found between 87Sr/86Sr of enamel and bone and between δ18O and δ13C in bone and hair reflect changes in sources of food and water in accordance with regionally typical migration journeys. The analysis of multiple stable isotopes delivered promising results, allowing us to narrow down the region of origin of deceased migrants and corroborate the information about the migration journey.

Combined use of 87Sr/86Sr and carbon isotopes with multielemental analysis for the geographical authentication of Tunisian and European olive oils

The geographical authentication in the agrifood industry has become a major issue to guarantee the quality of food products. Olive oil (OO) is particularly a complex matrix and establishing a reliable approach for linking OO samples to their origin is an analytical challenge. In this study, the isotopic composition of carbon, strontium and the concentrations of seventeen elements were determined in OOs from Tunisia, Southern France and the South Basque country. The preliminary results overlapped and showed that, taken individually, the isotopic and elemental approaches were not discriminant. A linear discriminant analysis applied to δ¹³C, ⁸⁷Sr/⁸⁶Sr and to the concentrations of 4 selected trace elements (Fe, Mn, V and Cr) allowed to classify, with high resolution, olive oils into 3 groups according to their provenance. The combination of the plant growing environment, the geological background, the mineral composition of the soil and the production process lead to a novel approach to deal with fraudulent practices in OO sector.

A Network Pharmacology and Multi-Omics Combination Approach to Reveal the Effect of Strontium on Ca2+ Metabolism in Bovine Rumen Epithelial Cells

Strontium (Sr) belongs to the same group in the periodic table as calcium (Ca). Sr level can serve as an index of rumen Ca absorption capacity; however, the effects of Sr on Ca²⁺ metabolism are unclear. This study aims to investigate the effect of Sr on Ca²⁺ metabolism in bovine rumen epithelial cells. The bovine rumen epithelial cells were isolated from the rumen of newborn Holstein male calves (n = 3, 1 day old, 38.0 ± 2.8 kg, fasting). The half maximal inhibitory concentration (IC50) of Sr-treated bovine rumen epithelial cells and cell cycle were used to establish the Sr treatment model. Transcriptomics, proteomics, and network pharmacology were conducted to investigate the core targets of Sr-mediated regulation of Ca²⁺ metabolism in bovine rumen epithelial cells. The data of transcriptomics and proteomics were analyzed using bioinformatic analysis (Gene Ontology and Kyoto Encyclopedia of genes/protein). Quantitative data were analyzed using one-way ANOVA in GraphPad Prism 8.4.3 and the Shapiro-Wilk test was used for the normality test. Results presented that the IC50 of Sr treatment bovine rumen epithelial cells for 24 h was 43.21 mmol/L, and Sr increased intracellular Ca²⁺ levels. Multi-omics results demonstrated the differential expression of 770 mRNAs and 2436 proteins after Sr treatment; network pharmacology and reverse transcriptase polymerase chain reaction (RT-PCR) revealed Adenosylhomocysteine hydrolase-like protein 2 (AHCYL2), Semaphoring 3A (SEMA3A), Parathyroid hormone-related protein (PTHLH), Transforming growth factor β2 (TGF-β2), and Cholesterol side-chain cleavage enzyme (CYP11A1) as potential targets for Sr-mediated Ca²⁺ metabolism regulation. Together these results will improve the current comprehension of the regulatory effect of Sr on Ca²⁺ metabolism and pave a theoretical basis for Sr application in bovine hypocalcemia.

Isotope Fingerprinting as a Backup for Modern Safety and Traceability Systems in the Animal-Derived Food Chain

In recent years, due to the globalization of food trade and certified agro-food products, the authenticity and traceability of food have received increasing attention. As a result, opportunities for fraudulent practices arise, highlighting the need to protect consumers from economic and health damages. In this regard, specific analytical techniques have been optimized and implemented to support the integrity of the food chain, such as those targeting different isotopes and their ratios. This review article explores the scientific progress of the last decade in the study of the isotopic identity card of food of animal origin, provides the reader with an overview of its application, and focuses on whether the combination of isotopes with other markers increases confidence and robustness in food authenticity testing. To this purpose, a total of 135 studies analyzing fish and seafood, meat, eggs, milk, and dairy products, and aiming to examine the relation between isotopic ratios and the geographical provenance, feeding regime, production method, and seasonality were reviewed. Current trends and major research achievements in the field were discussed and commented on in detail, pointing out advantages and drawbacks typically associated with this analytical approach and arguing future improvements and changes that need to be made to recognize it as a standard and validated method for fraud mitigation and safety control in the sector of food of animal origin.

Human migration in the eastern Tianshan Mountains between the 7th and 12th centuries

OBJECTIVE

Mid- to late-Holocene large-scale population migration profoundly impacted the interaction of ethnic groups and cultures across Eurasia, notably in Central Asia. However, due to a lack of thorough historical documents, distinctive burial items, and human remains, the process of population migration during this historical era in the area is still unclear. Using an interdisciplinary approach at the Lafuqueke (LFQK) cemetery, this study investigates the spatiotemporal processes and explores the factors that influenced human migration in the eastern Tianshan Mountains between the 7th and 12th centuries.

MATERIALS AND METHODS

In this study, tooth enamel from 56 human remains found in the LFQK cemetery in Hami Basin, eastern Tianshan Mountains, is examined for strontium and lead isotopes.

RESULTS

The early, middle, and late phases of migration might potentially be represented by a three-phase migration model, according to the isotopic study. The highest proportion of the early phase (ca. 7th-mid 7th century) comprised non-locals (54.55%), although this percentage decreased in the middle phase (mid 7th-mid 8th centuries, 30.77%). After the 10th century, the proportion of non-locals again fell (16.13%).

CONCLUSION

In this study, the interdisciplinary approach was employed to propose a new model for the diachronic changes that accompanied human migration and cultural interaction in the eastern Tianshan Mountains and identified geopolitics as a significant factor influencing the migratory behavior of LFQK population in this region between the 7th and 12th centuries.

Strontium isotope ratios in kidney stones reveal the environmental implications for humans in Beijing, China

Kidney stones are a common disease that threatens human health on a global scale and are closely related to the contemporary environment. The strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) has been widely used to trace the migration of ancient humans through bones and teeth, which recorded their bioavailable Sr from the environment. However, no ⁸⁷Sr/⁸⁶Sr data for kidney stones have been reported. Therefore, this study explored the Sr content of kidney stones and reported their ⁸⁷Sr/⁸⁶Sr data for the first time to reflect the environmental implications for humans; 66 calcium oxalate kidney stones collected in Beijing were measured for calcium (Ca), magnesium (Mg) and strontium (Sr) content to explore Sr distribution behavior in kidney stones, and 17 samples were tested for strontium isotopes. Ca and Mg had a joint effect on the Sr content of kidney stones, with magnesium having a stronger effect, whereas ⁸⁷Sr/⁸⁶Sr values were unaffected by these elements. The ⁸⁷Sr/⁸⁶Sr values of kidney stones ranged from 0.709662 to 0.710990, within the range of environmental soil and water in Beijing. Drinking water and surface soils (representing food sources) mainly contributed to the bioavailable Sr of kidney stones, while sea spray and dust storm did not. This study is the first to report ⁸⁷Sr/⁸⁶Sr values for kidney stones. Evidence of Sr isotope ratios in kidney stones reveals environmental implications for humans and bioavailable Sr sources, demonstrating a great potential of Sr isotope ratios at the intersection of life and environmental sciences.

Geographical origin traceability of Sengcu rice using elemental markers and multivariate analysis

Multi-element analysis combined with chemometric method has been used to investigate the distinguish between Sengcu rice and other types of rice origins in Vietnam. In Sengcu rice, As, Ba Sr, Pb, Ca, Se were confirmed as the key elements for geographical traceability among three fields of Lao Cai, whereas Al, Ca, Fe, Mg, Ag, As were major factors to distinguish between Sengcu and other types of rice. Based on linear discriminant analysis and partial least squares-discriminant analysis model, overall correct identification rates distinguishing between Sengcu and other types of rice were approximately 100% in both training and validation test. Moreover, to distinguish geographical origin of Sengcu rice samples, these rates vary from 80% to 99%. These results suggest the presence of food adulteration illustrated in the latter.

Creating communities of care: Sex estimation and mobility histories of adolescents buried in the cemetery of St. Mary Magdalen leprosarium (Winchester, England)

Objectives

This study examines the biological sex and geographical origins of adolescents buried at the St Mary Magdalen leprosarium (Winchester, UK). The data are combined with archaeological and palaeopathological evidence to broaden the understanding of mobility and its relationship to leprosy and leprosaria in Medieval England.

Materials and Methods

Nineteen individuals (~10–25 at death) with skeletal lesions diagnostic of leprosy were analyzed using standard osteological methods. Amelogenin peptides were extracted from five individuals whose biological sex could not be assessed from macroscopic methods. Enamel samples were analyzed to produce ⁸⁷Sr/⁸⁶Sr and δ¹⁸O values to explore mobility histories.

Results

Amelogenin peptides revealed three males and two females. Tooth enamel samples provided an ⁸⁷Sr/⁸⁶Sr ratio range from 0.7084 to 0.7103 (mean 0.7090, ±0.0012, 2σ). δ¹⁸O_P values show a wide range of 15.6‰–19.3‰ (mean 17.8 ± 1.6‰ 2σ), with corresponding δ¹⁸O_DW values ranging from −9.7‰ to −4.1‰ (mean −6.3 ± 2.4‰ 2σ).

Discussion

Amelogenin peptide data reveal the presence of adolescent females with bone changes of leprosy, making them the youngest confirmed females with leprosy in the archaeological record. Results also show at least 12 adolescents were local, and seven were from further afield, including outside Britain. Since St. Mary Magdalen was a leprosarium, it is possible that these people traveled there specifically for care. Archaeological and palaeopathological data support the notion that care was provided at this facility and that leprosy stigma, as we understand it today, may not have existed in this time and place.

Olive Oil Traceability Studies Using Inorganic and Isotopic Signatures: A Review

The olive oil industry is subject to significant fraudulent practices that can lead to serious economic implications and even affect consumer health. Therefore, many analytical strategies have been developed for olive oil’s geographic authentication, including multi-elemental and isotopic analyses. In the first part of this review, the range of multi-elemental concentrations recorded in olive oil from the main olive oil-producing countries is discussed. The compiled data from the literature indicates that the concentrations of elements are in comparable ranges overall. They can be classified into three categories, with (1) Rb and Pb well below 1 µg kg⁻¹; (2) elements such as As, B, Mn, Ni, and Sr ranging on average between 10 and 100 µg kg⁻¹; and (3) elements including Cr, Fe, and Ca ranging between 100 to 10,000 µg kg⁻¹. Various sample preparations, detection techniques, and statistical data treatments were reviewed and discussed. Results obtained through the selected analytical approaches have demonstrated a strong correlation between the multi-elemental composition of the oil and that of the soil in which the plant grew. The review next focused on the limits of olive oil authentication using the multi-elemental composition method. Finally, different methods based on isotopic signatures were compiled and critically assessed. Stable isotopes of light elements have provided acceptable segregation of oils from different origins for years already. More recently, the determination of stable isotopes of strontium has proven to be a reliable tool in determining the geographical origin of food products. The ratio ⁸⁷Sr/⁸⁶Sr is stable over time and directly related to soil geology; it merits further study and is likely to become part of the standard tool kit for olive oil origin determination, along with a combination of different isotopic approaches and multi-elemental composition.

Nutrient alloying elements in biodegradable metals: a review

As a new generation of biomedical metallic materials, biodegradable metals have become a hot research topic in recent years because they can completely degrade in the human body, thus preventing secondary surgery, and reducing the pain and economic burden for patients. Clinical applications require biodegradable metals with adequate mechanical properties, corrosion resistance, and biocompatibility. Alloying is an important method to create biodegradable metals with required and comprehensive performances. Since nutrient elements already have important effects on various physiological functions of the human body, the alloying of nutrient elements with biodegradable metals has attracted much attention. The present review summarizes and discusses the effects of nutrient alloying elements on the mechanical properties, biodegradation behavior, and biocompatibility of biodegradable metals. Moreover, future research directions of biodegradable metals with nutrient alloying elements are suggested.

Determination of Sr–Nd–Pb Isotopic Ratios of Rock Reference Materials Using Column Separation Techniques and TIMS

Thermal ionization mass spectrometry (TIMS) can provide highly accurate strontium (Sr), neodymium (Nd), and lead (Pb) isotope measurements for geological and environmental samples. Traces of these isotopes are useful for understanding crustal reworking and growth. In this study, we conducted a sequential separation of Sr, Nd, and Pb and subsequently measured the 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios of 13 widely used rock certified reference materials (CRMs), namely BCR-2, BHVO-2, GSP-2, JG-1a, HISS-1, JLk-1, JSd-1, JSd-2, JSd-3, LKSD-1, MAG-1, SGR-1, and 4353A, using TIMS. In particular, we reported the first isotopic ratios of Sr, Nd, and Pb in 4353A, Sr and Nd in HISS-1 and SGR-1, and Sr in JLk-1, JSd-2, JSd-3, and LKSD-1. The Sr–Nd–Pb isotopic compositions of most in-house CRMs were indistinguishable from previously reported values, although the Sr and Pb isotopic ratios of GSP-2, JSd-2, JSd-3, and LKSD-1 obtained in different aliquots and/or batches varied slightly. Hence, these rock reference materials can be used for monitoring the sample accuracy and assessing the quality of Sr–Nd–Pb isotope analyses.

Isotherm and Kinetic Modeling of Strontium Adsorption on Graphene Oxide

In this study, graphene oxide (GO) was synthesized using Hummers method. The synthesized GO was characterized using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) nitrogen adsorption. The analyses confirmed the presence of oxygen functional groups (C=O and C-O-C) on the GO surface. These oxygen functional groups act as active sites in the adsorption Sr (II). The BET analysis revealed the surface area of GO of 232 m²/g with a pore volume of 0.40 cm³/g. The synthesized GO was used as an adsorbent for removing Sr (II) from aqueous solutions. The adsorption equilibrium and kinetic results were consistent with the Langmuir isotherm model and the pseudo-second-order kinetic model. A maximum strontium adsorption capacity of 131.4 mg/g was achieved. The results show that the GO has an excellent adsorption capability for removing Sr (II) from aqueous solutions and potential use in wastewater treatment applications.

Silver Linings at the Dawn of a “Golden Age”

Nearly four decades after the first applications of strontium isotope analyses in archaeology and paleoecology research, it could be said that we are entering a “Golden Age”. Here, we reflect on major past developments and current strengths in strontium isotope research, as well as speculate on future directions. We review (1) the currently limited number of (but much needed) controlled feeding experiments, (2) recent advances in isoscape mapping and spatial assignment, and (3) the strength of multi-proxy approaches (including both the integration of strontium isotopes with other isotope systems and complementary techniques such as ancient DNA analyses). We also explore the integration of strontium isotope research with other types of paleoecological or archaeology data, as well as with evidence and interpretative frameworks from other fields (such as conservation ecology, conservation paleobiology or history). This blending is critical as we seek to advance the field beyond simply distinguishing local or relatively sedentary individuals from those that were non-local or highly mobile. We finish with a call for future research centered on balancing methodological developments and novel applications with critical self-reflection, deeper theoretical considerations and cross-disciplinarity.

The geographic distribution of bioavailable strontium isotopes in Greece - A base for provenance studies in archaeology

Sr isotopes are a powerful tool used to reconstruct human mobility in archaeology. This requires extensive bioavailable ⁸⁷Sr/⁸⁶Sr baselines used as reference for deciphering potential areas of origin. We define the first extensive bioavailable Sr isotope baselines for the different geographical regions and surface lithologies of Greece by combining new Sr data with previously published bioavailable ⁸⁷Sr/⁸⁶Sr data. We present 82 new Sr concentrations and ⁸⁷Sr/⁸⁶Sr signatures of plants, soil leachates, surface waters and spring waters from Central Greece and combine these with published baseline values from all over Greece. We define individual baselines for ten of the thirteen geographical regions of Greece. We also provide soil leachate ⁸⁷Sr/⁸⁶Sr ratios from the two archaeological Bronze Age sites of Kirrha and Ayios Vasileios in Central and Southern Greece and demonstrate the validity and applicability of the new baselines for these sites. The bioavailable ⁸⁷Sr/⁸⁶Sr compositions of Central Greece define a narrow range of ⁸⁷Sr/⁸⁶Sr values between 0.70768 - 0.71021, with the widest range observed for the soil leachates. Sr derived from carbonate weathering appears to be the most important Sr source sampled by the proxies. There is an overall larger variability in baseline ranges of the different geographical regions, the narrowest is that for West Greece and the widest that for West Macedonia. In addition, we computed statistical Sr isotope ranges for the five main surface lithological groups characterising the sampling sites of the various proxies. Narrowly ranged, unradiogenic bioavailable Sr isotope signatures are typical of areas characterised by igneous outcrops as well as by Cenozoic and Mesozoic sediments. Areas, where Palaeozoic and Precambrian bedrock outcrops dominate, produce significantly wider ranges. Our study promotes the usefulness of multi-proxy baselines for geographical reference purposes and thus their promising applicability for future human mobility studies.

Specificity and Origin of the Stability of the Sr Isotopic Ratio in Champagne Wines

The ⁸⁷Sr/⁸⁶Sr ratio of 39 Champagnes from six different brands, originating from the whole “Appellation d’Origine Contrôlée” (AOC) Champagne was analyzed to establish a possible relation with the geographical origin. Musts (i.e., grape juice) and base wines were also analyzed to study the evolution of the Sr isotopic ratio during the elaboration process of sparkling wine. The results demonstrate that there is a very homogeneous Sr isotopic ratio (⁸⁷Sr/⁸⁶Sr = 0.70812, n = 37) and a narrow span of variability (2σ = 0.00007, n = 37). Moreover, the Sr concentrations in Champagnes have also low variability, which can be in part explained by the homogeneity of the bedrock in the AOC Champagne. Measurements of the ⁸⁷Sr/⁸⁶Sr ratio from musts and base wines show that blending during Champagne production plays a major role in the limited variability observed. Further, the ⁸⁷Sr/⁸⁶Sr of the musts were closely linked to the ⁸⁷Sr/⁸⁶Sr ratio of the vineyard soil. It appears that the ⁸⁷Sr/⁸⁶Sr of the product does not change during the elaboration process, but its variability decreases throughout the process due to blending. Both the homogeneity of the soil composition in the Champagne AOC and the blending process during the wine making process with several blending steps at different stages account for the unique and stable Sr isotopic signature of the Champagne wines.

Resolving Severe Elemental Isobaric Interferences with a Combined Atomic and Molecular Ionization Source-Orbitrap Mass Spectrometry Approach: The 87Sr and 87Rb Geochronology Pair

Many fields of basic and applied sciences, including geochronology, astronomy, metabolism, etc., rely on the ability of mass spectrometry to obtain isotope ratio measurements having a high degree of certainty. The inability to resolve difficult isobaric interferences plagues certain measurements. A combined atomic and molecular (CAM) ionization source has been interfaced to a high-field Orbitrap mass spectrometer to alleviate severe atomic, isobaric interferences. This work examines the geochronologically significant ⁸⁷Sr and ⁸⁷Rb isotope pair. The mass difference between ⁸⁷Sr and ⁸⁷Rb is approximately 0.3 mDa, requiring a minimum resolving power (R = m/Δm) of ∼290,000, a value ∼30× higher than available with sector-field elemental mass spectrometers. Under ultrahigh-resolution conditions, Sr isotope ratio accuracy and precision were evaluated using NIST Sr SRM 987, yielding precision values of <0.1% relative standard deviation (RSD) for the major isotopes and a calculated LOD of 2 pg mL^-1 (120 fg of Sr for a 60 μL injection). In addition to manipulating the signal transient length, the total number of ions in the electrostatic trap and the ⁸⁷Sr/⁸⁷Rb concentration ratio were found to influence resolution. Ultimately, the isotopes were baseline-resolved with a calculated mass resolution of >1.7M. At equal ⁸⁷Sr and ⁸⁷Rb intensities, ⁸⁷Sr/⁸⁶Sr was measured as 0.71294 (a relative error of only 0.37%) with a precision of 0.097% RSD, clearly reflecting the alleviation of the isobaric interference.

Analytical strategies for Sr and Pb isotopic signatures by MC-ICP-MS applied to the authentication of Champagne and other sparkling wines

Wine is one of the most counterfeit product and therefore, requires certifying of its origin and provenance. For authentication purposes, analytical strategies for the determination of Sr and Pb isotopic ratios were adapted for Champagne and sparkling wines. All analytical steps have been carefully adapted and optimized regarding sample preparation, mineralization, and purification by resins as well as isotopic composition measurements on 3 different MC ICP-MS instruments. Further, a global approach using an "in-house" reference material of Champagne (ChRM) was realized and used throughout as well as routine analytical conditions to guaranty samples isotopic quality determination over 3 years. These developments allowed to select the best conditions at all steps for reaching the best precision and accuracy to be used under routine conditions for samples origin discrimination. The best condition of mineralization was obtained with a hot block system allowing both efficiency in digestion and high sample throughput. Detailed conditions of purification for both Sr and Pb isotopes were also optimized and discussed. These different optimization steps on the whole analytical chain allowed to estimate a global precision suitable to be used routinely to discriminate the origin of different Champagne samples. For Sr isotopic analysis (⁸⁷Sr/⁸⁶Sr), the overall external precision based on preparation replicates of ChRM was 2σ = 0.000024 (n = 36) and for the Pb isotopes analysis (²⁰⁸Pb/²⁰⁶Pb), the precision obtained on ChRM was 2σ = 0.0024 (n = 15). Finally, we have applied these developments by combining both Sr and Pb isotopic ratios in order to discriminate the origin of sparkling wines from around the world. The combined isotopic signature, using both Sr and Pb isotopes ratios, permitted a clear discrimination between certified Champagne wines and other European and Non-European sparkling wines.

Strontium isotope evidence for a trade network between southeastern Arabia and India during Antiquity

Cotton (Gossypium sp.), a plant of tropical and sub-tropical origin, appeared at several sites on the Arabian Peninsula at the end of the 1st mill. BCE-beginning of the 1st mill. CE. Its spread into this non-native, arid environment is emblematic of the trade dynamics that took place at this pivotal point in human history. Due to its geographical location, the Arabian Peninsula is connected to both the Indian and African trading spheres, making it complex to reconstruct the trans-continental trajectories of plant diffusion into and across Arabia in Antiquity. Key questions remain pertaining to: (1) provenance, i.e. are plant remains of local or imported origin and (2) the precise timing of cotton arrival and spread. The ancient site of Mleiha, located in modern-day United Arab Emirates, is a rare and significant case where rich archaeobotanical remains dating to the Late Pre-Islamic period (2nd-3rd c. CE), including cotton seeds and fabrics, have been preserved in a burned-down fortified building. To better understand the initial trade and/or production of cotton in this region, strontium isotopes of leached, charred cotton remains are used as a powerful tracer and the results indicate that the earliest cotton finds did not originate from the Oman Peninsula, but were more likely sourced from further afield, with the north-western coast of India being an isotopically compatible provenance. Identifying the presence of such imported cotton textiles and seeds in southeastern Arabia is significant as it is representative of the early diffusion of the crop in the region, later to be grown extensively in local oases.

A strontium isotope baseline of Cyprus. Assessing the use of soil leachates, plants, groundwater and surface water as proxies for the local range of bioavailable strontium isotope composition

In this study, a strontium isotope baseline for Cyprus is presented. The aim of the study was two-fold; first to provide an environmental multi-proxy-based baseline (water/plants/soil leachates) suitable for archaeological provenance and mobility studies, food source authentication, and forensic investigations; and second, to contribute to the debate around which proxy (or combination of proxies) might be most suitable to define bioavailable fractions of strontium in geologically complex areas also exposed to sea-spray and other Sr-bearing aerosols. Lowest bioavailable strontium isotope signatures range is found within terranes dominated by ophiolites, where ⁸⁷Sr/⁸⁶Sr ratios range from 0.7055 to 0.7081, however, results reveal a high degree of variability in bioavailable ⁸⁷Sr/⁸⁶Sr ratios, both spatially, along depth profiles and amongst the different proxies. A narrower range of bioavailable Sr isotope signatures is observed within the Circum Troodos Sedimentary Successions (C.T.S.S.), both in spatial distribution and between different proxies. Observed range is ⁸⁷Sr/⁸⁶Sr = 0.7079 to 0.7089 in areas dominated by pre-Quaternary C.T.S.S., and ⁸⁷Sr/⁸⁶Sr ratios = 0.7076 to 0.7086 in areas covered by Quaternary C.T.S.S., revealing the lithologies to be very homogenous with respect to bioavailable strontium ratios. Intra-site variations in three archaeological sites (multiple samples from each site from within a 500 m radius) within the pre-Quaternary and Quaternary C.T.S.S. are smaller than inter-site variations, suggesting that tracing studies inferred from baselines sampled within a limited spatial area could lead to erroneous conclusions regarding provenance. The study points to the necessity for conducting multi-proxy, spatially extensive sampling to adequately characterize complex geological areas, if these should serve as reliable reference areas in provenance studies.

Geographic variation of Sr and S isotope ratios in bottled waters in Japan and sources of Sr and S

The geographic distribution of the stable isotope ratio of Sr (⁸⁷Sr/⁸⁶Sr) is useful for identifying the provenance of drinking water, organisms, and agricultural products. To explore how environmental factors influence this ratio, we determined the ⁸⁷Sr/⁸⁶Sr, sulfur isotope ratio (δ³⁴S), and elemental composition of 208 commercially available bottled waters in Japan, and compared them with the ⁸⁷Sr/⁸⁶Sr values of groundwater, rainwater, rocks, and vegetables from similar localities. We classified the bottled waters into seven categories based on the geology of their source aquifers. The ⁸⁷Sr/⁸⁶Sr and concentrations of several elements (Ca, K, Si, Rb, and Ba) of the bottled waters differed with the aquifer rock type and were well correlated with the ⁸⁷Sr/⁸⁶Sr of reported spring waters, indicating that bottled water, like other groundwater, reflects the lithology and chemistry of its aquifer. The ⁸⁷Sr/⁸⁶Sr of bottled water, taken as a proxy for groundwater, showed regional variations consistent with those of rocks and vegetables, demonstrating that an ⁸⁷Sr/⁸⁶Sr map of water and agricultural products has value for determining the production areas of these substances. However, the value and range of ⁸⁷Sr/⁸⁶Sr differed among these three materials, and the degree of the difference between groundwater and rock depended on the rock type. An analysis of geochemical data from rocks and rainwater suggests that groundwater contains Sr and additional S derived from atmospheric sources such as rainwater and sea salt aerosols. The atmospheric contribution of Sr to groundwater is greatest in areas of siliceous sedimentary rocks with low Sr concentrations and high resistance to weathering. A weak correlation of δ³⁴S of bottled waters with ⁸⁷Sr/⁸⁶Sr indicates the usefulness of maps of combined Sr and S isotope ratios for groundwater provenance. This study shows that for accurate provenance determinations of groundwater, organisms, and agricultural products, it is essential to better quantify the contributions of Sr and S from the atmosphere as well as from rocks and human activities.

Ultra-High Resolution Elemental/Isotopic Mass Spectrometry (m/Δm > 1,000,000): Coupling of the Liquid Sampling-Atmospheric Pressure Glow Discharge with an Orbitrap Mass Spectrometer for Applications in Biological Chemistry and Environmental Analysis

Many fundamental questions of astrophysics, biochemistry, and geology rely on the ability to accurately and precisely measure the mass and abundance of isotopes. Taken a step further, the capacity to perform such measurements on intact molecules provides insights into processes in diverse biological systems. Described here is the coupling of a combined atomic and molecular (CAM) ionization source, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) microplasma, with a commercially available ThermoScientific Fusion Lumos mass spectrometer. Demonstrated for the first time is the ionization and isotopically resolved fingerprinting of a long-postulated, but never mass-spectrometrically observed, bi-metallic complex Hg:Se-cysteine. Such a complex has been implicated as having a role in observations of Hg detoxification by selenoproteins/amino acids. Demonstrated as well is the ability to mass spectrometrically-resolve the geochronologically important isobaric ⁸⁷Sr and ⁸⁷Rb species (Δm ~ 0.3 mDa, mass resolution m/Δm ≈ 1,700,000). The mass difference in this case reflects the beta-decay of the ⁸⁷Rb to the stable Sr isotope. These two demonstrations highlight what may be a significant change in bioinorganic and atomic mass spectrometry, with impact expected across a broad spectrum of the physical, biological, and geological sciences. Graphical Abstract "".

Modelling strontium isotopes in past biospheres - Assessment of bioavailable 87Sr/86Sr ratios in local archaeological vertebrates based on environmental signatures

⁸⁷Sr/⁸⁶Sr isotopic ratios in skeletal remains of archaeological vertebrates are used for provenance analysis since long. However, the definition of the past bioavailable isotopic ratio at the site of recovery is not known beforehand and geological maps can provide no more than gross expectations. Therefore, the assessment of the "local Sr isotopic signature" is still of crucial importance. In this study, we present a tool for the prediction of such local isotopic signatures by creating a concentration weighted mixing model that links lithospheric, biospheric, and atmospheric strontium per site. The major strontium sources and their input into an animal's body were assessed by choosing elemental strontium and its isotopic signature in groundwater, soil, vegetation, and precipitation as components for the mixing model, augmented by literature values. The model was applied to 24 sites located in the alpine transect of the Inn-Eisack-Adige-Brenner passage across the European Alps, a passage used since the Mesolithic. Predicted local bioavailable ⁸⁷Sr/⁸⁶Sr ratios were compared with measured values from locally excavated archaeozoological bone samples from three taxa of large and mainly residential vertebrates (cattle, pig, red deer) to verify the models' accuracy. With regard to the fact that the environmental samples predict the past local bioavailable ⁸⁷Sr/⁸⁶Sr at a specific site while the vertebrates had different and species-specific home ranges, thereby integrating strontium from a region of primarily unknown size, the model is capable of assigning reasonable expectation values. For 11 sites, up to 100% of the vertebrate isotopic signatures were correctly predicted. Mismatches at the remaining sites are explainable by special environmental factors, and also the fact that some import of animals can never be excluded beforehand. Suggestions for site-specific adjustments of the model are made.

Applying the principles of isotope analysis in plant and animal ecology to forensic science in the Americas

The heart of forensic science is application of the scientific method and analytical approaches to answer questions central to solving a crime: Who, What, When, Where, and How. Forensic practitioners use fundamentals of chemistry and physics to examine evidence and infer its origin. In this regard, ecological researchers have had a significant impact on forensic science through the development and application of a specialized measurement technique-isotope analysis-for examining evidence. Here, we review the utility of isotope analysis in forensic settings from an ecological perspective, concentrating on work from the Americas completed within the last three decades. Our primary focus is on combining plant and animal physiological models with isotope analyses for source inference. Examples of the forensic application of isotopes-including stable isotopes, radiogenic isotopes, and radioisotopes-span from cotton used in counterfeit bills to anthrax shipped through the U.S. Postal Service and from beer adulterated with cheap adjuncts to human remains discovered in shallow graves. Recent methodological developments and the generation of isotope landscapes, or isoscapes, for data interpretation promise that isotope analysis will be a useful tool in ecological and forensic studies for decades to come.

Strontium isotope ratios of human hair record intra-city variations in tap water source

The oxygen (¹⁸O/¹⁶O) isotope analysis of hair is commonly applied to reconstruct an individual’s residence history. However, region-of-origin as determined from oxygen isotope values (δ¹⁸O) alone is often spatially indistinct. Adding additional geochemical recorders can refine region-of-origin estimates. In this capacity, strontium (⁸⁷Sr/⁸⁶Sr) isotope analysis has attracted increased interest. While ⁸⁷Sr/⁸⁶Sr reflects the influences of local geology, ⁸⁷Sr/⁸⁶Sr of hair includes both external environmental signals as well as the internal dietary indicators. To better understand the impact of these contributions to the spatial signal encoded within ⁸⁷Sr/⁸⁶Sr of hair, human hair was collected from three locations within Salt Lake City, Utah along with the donor’s sex. The ⁸⁷Sr/⁸⁶Sr and δ¹⁸O of hair and local tap water were measured. There were no significant relationships between sex and either δ¹⁸O or ⁸⁷Sr/⁸⁶Sr of hair, nor between collection location and the δ¹⁸O of hair. However, we found significant associations between collection location and ⁸⁷Sr/⁸⁶Sr of hair. These findings suggest that interactions with local water may be an important source of Sr to human hair and that the ⁸⁷Sr/⁸⁶Sr of hair may have the capacity to record differences in ⁸⁷Sr/⁸⁶Sr of tap waters on small spatial scales.