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Ohne Zusammenfassung     

Sr isotope measurements in beef—analytical challenge and first results

The strontium isotope ratio ((87)Sr/(86)Sr) in beef, derived from 206 European cattle, has been measured. These cattle were located in 12 different European regions within France, Germany, Greece, Ireland, Italy, Spain and the UK. As animal protein is known to be a difficult material on which to conduct Sr isotope analysis, several investigations were undertaken to develop and improve the sample preparation procedure. For example, Sr isotope analysis was performed directly on freeze-dried meat and defatted dry mass from the same samples. It was found that enormous differences-sometimes exceeding the measurement uncertainty-could occur between the fractions and also within one sample even if treated in the same manner. These variations cannot be definitely allocated to one cause but are most likely due to inhomogeneities caused by physiological and biochemical processes in the animals as post mortem contamination during analytical processing could be excluded. For further Sr isotope measurements in meat, careful data handling is recommended, and for the authentic beef samples within this project, it was decided to use only freeze-dried material. It can be demonstrated, however, that Sr isotope measurements in beef proteins are a valuable tool for authentication of geographic origin. Although partly overlapping, some of the European sampling sites could be discriminated even by only using (87)Sr/(86)Sr.     

Spatial variability of 2H and 18O composition of meteoric freshwater lakes in Scotland

Coastal regions, and in particular islands where precipitation from clouds formed out at sea occurs for the first time, are prime candidates for regions where ²H and ¹⁸O composition of precipitation will deviate significantly from the global mean geographic and physiographic trends of vapour-transport patterns. The results reported here are the outcome of a study that aimed to test this hypothesis by ‘isotopographically’ mapping the characteristic δ²H and δ¹⁸O signatures of Scottish freshwaters. The resulting isotope abundance landscapes or ‘isoscapes’ will underpin studies aiming to authenticate origin of Scottish produce but may also offer a baseline against which environmental changes could be assessed. Between April 2011 and May 2012 freshwater samples were collected from 127 different freshwater lochs and reservoirs across Scotland, and analysis results were compared to precipitation data provided by the British Geological Survey. Here we present the results of the ²H and ¹⁸O analyses of these water samples as well as the first detailed Scotland freshwater isoscapes with a grid resolution of about 5 × 5 km (0.05 degrees).     

Multi-element (H,C,N,S) stable isotope characteristics of lamb meat from different European regions

Multi-element (H,C,N,S) stable isotope ratio analysis was tested for its suitability as a means for geographical provenance assignment of lamb meat from several European regions. The defatted dry matter (crude protein fraction) from lamb meat was found to be a suitable probe for "light" element stable isotope ratio analysis. Significant differences were observed between the multi-element isotope ratios of lamb samples from different regions. The mean hydrogen isotopic ratios of the defatted dry matter from lamb were found to be significantly correlated with the mean hydrogen isotopic ratios of precipitation and groundwater in the production regions. Carbon and nitrogen isotopic ratios were influenced by feeding practices and climate. Sulfur isotopic ratios were influenced by geographical location and surface geology of the production region. The results permitted differentiation of lamb meat, from most production regions, by inspection. However, more sophisticated evaluation of the data using multivariate methods, such as linear discriminant analysis, achieved 78% correct classification.