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.

Isotope abundance ratios of sr in wine provenance determinations, in a tree-root activity study, and of pb in a pollution study on tree-rings.

Abstract In this contribution, the various and fundamentally different uses and applications of isotope signatures (of both heavy and light elements) are discussed. Examples are given for the successful use of (87)Sr/(86)Sr in uncovering fraud in wine trade. Also, in an experiment related to "Waldsterben", (87)Sr/(86)Sr analyses reveal rather unexpected responses of spruces and maple-trees to mechanical damage of their roots. In another study, from (206)Pb/(207)Pb (and (208)Pb/(207)Pb) analyses of tree growth-rings it is demonstrated that they do not accurately record lead burdens in the environment. This is contrary to current views on the subject of tree-rings as reliable banks of past heavy metal pollutions of the biosphere. Furthermore, new perspectives of applications of isotopes in biological tissues, including those of cosmogenic and nucleogenic origin will be shortly outlined.