Effect of the vintage year on strontium isotopic ratio (87Sr/86Sr) of wines: a Portuguese case study.

Polyphenolic composition of Croatian wines with different geographical origins

Isolation of strontium pools and isotope ratios in modern human hair

The increase in wine consumption is accompanied by raising in the number of counterfeit wine products. In this regard, the task of establishing its authenticity is relevant. The purpose of this study was to build models for identifying the varietal and geographical origin of wines using machine learning methods based on the mineral composition of 426 wine samples. The elemental analysis of wines was performed using inductively-coupled plasma atomic emission and mass spectrometry methods. Discriminant Analysis showed the presence of cluster structures of wine samples relative to varietal and regional origin, which allowed the development of identification models. Classification models were built using machine learning methods: Automated neural networks, General classification and regression trees, Boosted trees classifications and regression, Random Forest, Support vector machine, k-nearest neighbor, Naïve Bayes Classifiers. At stages of solving the problem of wine identification by all methods, with the exception of Naïve Bayes Classifiers, the threshold of prediction accuracy exceeded 90%, of which the Automated neural networks method showed the best results. When determining the variety by contribution to the classification model, Rb, K, and Ca dominated, while geographical origin was dominated by Li, Mg, and Rb. It is proposed to use an ensemble approach to the classification of objects, involving the application of the voting principle, to increase the reliability of the forecast.

The possibility of establishing the varietal and territorial affiliation of wines by the content of rare earth elements (REE) in them was studied. ICP-OES and ICP-MS with subsequent chemometric processing of the results were applied to determine the elemental image of soils containing negligible REE amounts, grapes grown on these soils, and wine materials of Cabernet Sauvignon, Merlot, and Moldova varieties produced from these grapes. To stabilize and clarify wine materials, the traditional processing of wine materials with various types of bentonite clays (BT) was used, which turned out to be a source of REE in the wine material. Discriminant analysis revealed that the processed wine materials were homogeneous within one denomination and that those of different denominations were heterogeneous with respect to the content of REE. It was found that REE in wine materials were transferred from BT during the processing, and thus they can poorly characterize the geographical origin and varietal affiliation of wines. Analysis of these wine materials according to the intrinsic concentrations of macro- and microelements showed that they formed clusters according to their varietal affiliation. In terms of their influence on the varietal image of wine materials, REE are significantly inferior to macro- and microelements, but they enhance their influence to a certain extent when used together.

Fresh basalt and metabasalt dredged from the Mid-Atlantic Ridge were studied for Na, K, Rb, Sr, and H2O(+) contents, and strontium and hydrogen isotope ratios. Na, K, Rb, and Sr contents of these samples are within the range of those of oceanic tholeiite. H2O(+) content, strontium, and hydrogen isotope ratios vary widely. The variation in water content of metabasalt is apparently related to the chlorite content. The metamorphic temperature was about 550 °C based on the estimated δD value of chlorite. There is positive linear relationship between water content and strontium isotope ratio. Based on this relationship, the variation of strontium isotope ratio of the metabasalt was interpreted as follows: complete exchange occurred between strontium in the chlorite portion of the metabasalt and strontium in sea water (87Sr/86Sr ratio=0.7090), while the original strontium (87Sr/86Sr∼0.7023) was retained in the non-altered portion of the basalts.

炸药的深度比对与溯源对于爆炸案事件的侦破具有重大意义,以不同地域来源的原料或不同生产工艺生产的炸药,其组成元素的稳定同位素比值具有差异,因而稳定同位素比值可作为炸药深度比对与溯源的重要指标。稳定同位素比值质谱法(IRMS)作为一种高精度的稳定同位素比值测量手段,已逐渐发展成熟,与元素分析仪、气相色谱仪、液相色谱仪等仪器联用,在食品安全、环境保护、法庭科学等领域应用广泛。IRMS在炸药比对与溯源上亦发挥了重要作用,自1975年IRMS被应用于区分不同国家生产的三硝基甲苯(TNT)以来,IRMS已成功用于多种炸药的分析。但目前尚未见有文献系统地总结常见炸药的稳定同位素比值分析研究进展。该文介绍了稳定同位素比值分析的相关原理、仪器组成及特点,分别总结了硝酸铵、黑火药、TNT、太恩、黑索金等常见炸药的稳定同位素比值分析方法,汇总了文献报道的不同国家生产的硝酸铵、黑火药、TNT等炸药的稳定同位素比值。文章就不同炸药的稳定同位素比值差异、炸药生产、存储过程中相关因素对同位素比值的影响,爆炸前后稳定同位素比值的变化情况等内容进行了分析。本文还指出了目前炸药的稳定同位素比值分析研究中存在的问题,对可能的解决办法进行了讨论,对未来的发展方向提出了建议。

Wine geographical traceability is an important topic in the context of wine authentication and for that, many researchers worldwide have addressed this subject by developing different methodologies based on multivariate analysis of natural chemical composition data (inorganic or organic parameters) and isotopic signature. The goal of this work was to assess the potential of elemental composition and strontium isotope ratio (87Sr/86Sr) of wines from important wine-producing regions in Romania, located in relatively small geographical areas, in order to highlight reliable markers for wine geographical origin discrimination. Elemental profile determinations were performed by ICP-MS, GFAAS, and FAAS techniques after microwave acid digestion of the wine samples. The 87Sr/86Sr isotope ratio of the resulted extracts was determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS), after separating strontium and rubidium using cation-exchange chromatography with Dowex 50W-X8 resin and the complexation ability of the carboxylic acid EDTA. The variation of elemental composition (Ga, Sr, and Al), Ca/Sr ratio, and the 87Sr/86Sr ratio of the investigated wine clearly demonstrated that these variables are suitable tracers for wine geographic origin determination. The proposed methodology allowed a 100 % successful classification of wines according to the region of provenance.

Cremated bone fragments can be studied using structural, elemental, and isotope analyses in archaeological contexts to reconstruct funerary practices and understand past mobility and migrations of populations that practiced cremation. However, the potential of isotope analyses of cremated bone in forensic contexts remains heavily unexplored. The identification of fire victims can be complex as the remains can be extremely fragmented and commingled. The high temperatures (up to 1000°C and above) destroy most organic matter such that, obtaining reliable DNA from such intensively burned human remains is extremely difficult. Still, other signals present in bone, such as strontium concentrations and isotopes, are preserved during cremation, and could be used to assess the geographical origin of unidentified fire-affected individuals. Carbon and oxygen isotope ratios together with infrared analyses provide information about the burning conditions and could help understanding how a body was burned. Here, isotope and infrared analyses are carried out on fourteen recently deceased cremated individuals of known residential history from the UTK Donated Skeletal Collection curated by the Forensic Anthropology Center (Knoxville, Tennessee). By carrying out these measurements on different bones with different turnover rates (i.e., otic capsule of the petrous part of the temporal bone, femur, and rib), we endeavor to reconstruct life histories of recently deceased cremated individuals and gain new insights into cremation practices. The results highlight differences in carbon and oxygen isotopes between different skeletal elements and confirm their potential to gather information about the way a body was burned (e.g., temperatures, fuel used). Strontium concentrations and isotope ratios were also measured to assess the geographical origin of these individuals. The use of strontium isotope ratios, however, seem to have limitations for individuals born in the last few decades due to globalization of consumed food resources. Nevertheless, it is still possible to obtain information about the birthplace of older individuals (> 50 years) by analyzing strontium isotope ratios in the petrous part of their temporal bone, which retains a signal linked to the first few years of their lives when local resources were still used in larger quantities compared to today.

A mathematical procedure of multiple linear regression in combination with on-line liquid chromatography was applied for the measurement of Sr and Nd isotope ratios by multicollector ICP-MS in the presence of isobaric isotopes. The separation of Rb and Sr and the separation of Nd and Sm were accomplished by ion exchange chromatography with large volume injection. This mode of injection allowed wide flat-topped chromatographic peaks to be obtained while maintaining chromatographic resolution and avoiding sample dilution. The application of the multiple linear regression procedure to the raw chromatographic data allowed the determination of the isotope ratios of Sr or Nd without interferences from isobaric isotopes. For Sr measurements, the raw 87Sr/86Sr isotope ratio precision (0.006 to 0.010%) was similar to that of continuous sample introduction (ca. 0.003%) at the same concentration level (50 ng g−1). The mathematical procedure was first evaluated for the cation exchange separation of Rb and Sr. Strontium isotope ratios, obtained using NIST SRM 987, were in agreement with the certified values (bias ca. 0.01%). For the case of Nd and Sm, their chromatographic separation was accomplished by anion exchange using EDTA as mobile phase. Neodymium eluted at 12.8 minutes while samarium eluted at 17.5 minutes, showing flat-topped chromatographic peaks and maintaining baseline neodymium–samarium separation. Precise neodymium and samarium isotope ratios suitable for Nd–Sm dating could be measured by MC-ICP-MS using the proposed multiple linear regression procedure using only one cup configuration.

Use of SNIF-NMR and IRMS in combination with chemometric methods for the determination of chaptalisation and geographical origin of wines (the example of Slovenian wines)

Two promising isotope ratios, the δ18O of the water fraction, as extracted by azeotropic distillation, and the 87Sr/86Sr of the ash fraction were tested for their applicability to determine the geographic origin. In two sampling phases, in total 78 fresh poultry breast meat and 72 dried beef samples, independent from each other and originating from different countries, were analysed. The δ18O was measured with isotope ratio mass spectrometry and the isotope abundance ratio of 87Sr/86Sr with a multicollector inductively coupled plasma mass spectrometer. With δ18O it was possible to distinguish (p < 0.001) poultry and dried beef samples according to their country of origin. The beef data suggests that the procedure of processing is of only low additional influence on δ18O and, if so, it seems to reduce the initial between-country differences. The 87Sr/86Sr ratio did not give sufficient indications for differentiation by geographic origin in either poultry meat or dried beef in the smaller, first phase, data set and was therefore not further tested.

Anglo-Saxon origins investigated by isotopic analysis of burials from Berinsfield, Oxfordshire, UK

Stable isotope evidence for a marine origin of ophicalcites from the north-central Apennines (Italy)

The need to guarantee the geographical origin of food samples has become imperative in recent years due to the increasing amount of food fraud. Stable isotope ratio analysis permits the characterization and origin control of foodstuffs, thanks to its capability to discriminate between products having different geographical origins and derived from different production systems. The Framework 6 EU-project “TRACE” generated hydrogen (2H/1H), carbon (13C/12C), nitrogen (15N/14N), and sulphur (34S/32S) isotope ratio data from 227 authentic beef samples. These samples were collected from a total of 13 sites in eight countries. The stable isotope analysis was completed by combining IRMS with a thermal conversion elemental analyzer (TC/EA) for the analysis of δ(2H) and an elemental analyzer (EA) for the determination of δ(13C), δ(15N), and δ(34S). The results show the potential of this technique to detect clustering of samples due to specific environmental conditions in the areas where the beef cattle were reared. Stable isotope measurements highlighted statistical differences between coastal and inland regions, production sites at different latitudes, regions with different geology, and different farming systems related to the diet the animals were consuming (primarily C3- or C4-based or a mixed one).

The strontium (Sr) isotope ratio ((87)Sr/(86)Sr) and Sr content were used to trace the geographical origin of onions from Japan and other countries, including China, the United States of America, New Zealand, Australia, and Thailand. The mean (87)Sr/(86)Sr ratio and Sr content (dry weight basis) for onions from Japan were 0.70751 and 4.6 mg kg(-1), respectively, and the values for onions from the other countries were 0.71199 and 12.4 mg kg(-1), respectively. Linear discriminant analysis was performed to classify onions produced in Japan from those produced in the other countries based on the Sr data. The discriminant equation derived from linear discriminant analysis was evaluated by 10-fold cross validation. As a result, the origins of 92% of onions were correctly classified between Japan and the other countries.