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Schweitenkirchen, Germany

Isolab GmbH

Schweitenkirchen, Germany
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Lehn C.,Ludwig Maximilians University of Munich | Mutzel E.,Ludwig Maximilians University of Munich | Rossmann A.,Isolab GmbH
International Journal of Legal Medicine | Year: 2011

This paper presents a comparison of the isotopic ratios of hydrogen, carbon, nitrogen and sulphur of three pairings of hair and nail tissue taken from contemporary human remains. Our aim was to examine the possibility of a direct comparison of isotopic data in hair with that of nail tissue for forensic purposes. The results indicate that stable isotope ratios of the elements were best comparable between human scalp hair longer than 3 cm and the distal end of the nails. There were no distinct variations between finger and toenails. Our isotopic data for bulk hair and nail confirmed that hair samples were slightly enriched in 13C but depleted in 15N compared to nail samples. Furthermore, our data reveal that δ34S values in nail samples were more variable than in hair samples. Direct comparison of the corresponding segments of hair and nail samples may be difficult due to individual differences especially for δ15N and δ2H. Hair may have an isotopic composition more consistent with the ingested food within a specific time than is provided by nail. It can be concluded that once a hair is formed, no further metabolic changes of the isotopic pattern should occur. Nevertheless, our data suggest that there was a change in isotope ratios particularly for δ2H along the hair shaft. Interpretation of the isotope data in corresponding segments of hair and nail for forensic purposes must consider particular variations, especially for chronological considerations. © 2011 Springer-Verlag.

Lehn C.,Ludwig Maximilians University of Munich | Rossmann A.,Isolab GmbH | Graw M.,Ludwig Maximilians University of Munich
Science and Justice | Year: 2015

Stable isotope methods can be used to determine the provenance of unidentified corpses. Body tissue materials such as teeth, bone, hair and nail taken from mortal remains provide information of different time periods of an individuals' life from childhood to death. Tissues of newborns contain provenance information of different time periods during pregnancy of the child's mother. The results of stable isotope analyses of body residues of two adults and a newborn found in Germany between 2010 and 2012 are presented. To determine the geographic origin and movements of unknown individuals, stable isotopes of hydrogen, carbon, nitrogen and sulphur were analysed in hair and bone collagen samples. Amino acid composition and, as a consequence, δ2H, δ13C, δ15N, and δ34S values in human keratin and bone collagen are different. Consequently correction factors were determined to compare isotopic data of bone collagen with those of an extensive worldwide reference hair collection. The isotopic signatures in hair and in bone collagen samples were compared to geographical groups of reference hair samples by canonical discriminant analysis. The results served as the basis for providing provenance constraints for the unidentified persons as requested by the police and prosecution. Ultimately the individuals were identified; hence the isotopic provenance interpretations can be critically evaluated and are shown to be successful. © 2014 Forensic Science Society.

Lehn C.,Ludwig Maximilians University of Munich | Lihl C.,Ludwig Maximilians University of Munich | Rossmann A.,Isolab GmbH
Isotopes in Environmental and Health Studies | Year: 2015

To receive information about the duration of a person's stay abroad related to those questions in forensics, stable isotopes of H–C–N–S were analysed in beard hair samples from four young soldiers, who went from Fürstenfeldbruck (Bavaria, Germany) to Phoenix (Arizona, USA) on the same date for their pilot training over a time period of 3 months. All study subjects were almost of the same age, had similar physical constitutions and stayed at the same military bases for the whole study period. However, the results showed considerable individual variabilities. In Arizona, hair δ13C increased by 2.3 ‰ (±0.6) and δ34S decreased by 1.8 ‰ (±1.2). No remarkable shifts of hair δ15N and δ2H were observed. Significant shifts of δ13C or δ34S in the shaved beard hair samples occurred 8 or 9 days after arrival in Arizona, respectively. The time lag to receive the isotope signals in hair due to US diet correspond to the growth period that hair needs to cover the distance of 2–3 mm from its root to the surface of the skin. This implies that isotopic changes due to the consumption of food and drinks were incorporated almost immediately into the hair protein. Consequently, if connected with an isotopic change of the diet, short-term stays for only a few days might be clearly recognizable within the first millimetres of a scalp hair strand which includes the hair roots. © 2015, © 2015 Taylor & Francis.

Camin F.,IASMA Edmund Machinery Foundation | Perini M.,IASMA Edmund Machinery Foundation | Bontempo L.,IASMA Edmund Machinery Foundation | Fabroni S.,Italian Agricultural Research Council | And 9 more authors.
Food Chemistry | Year: 2011

Several isotopic (13C/12C, 15N/14N, 18O/16O, 2H/1H, 34S/32S) and chemical-physical parameters (pH, fruit weight, juice yield, titratable acidity, total soluble solids, skin resistance, flesh firmness, colorimetric characteristics, weight loss after harvesting, antioxidant activity, earliness index, total nitrogen, ascorbic acid, synephrine, anthocyanins and polyphenols, citric acid, malic acid, sucrose, glucose and fructose content) were investigated as potential markers of organically cultivated oranges, clementines, strawberries and peaches produced in Italy between 2006 and 2008, in experimental fields and in certified farms. The ratio 15N/14N, ascorbic acid and total soluble solids were shown to be the most significant variables for distinguishing between organically and conventionally cultivated fruits. It was not possible to define general threshold limits typical of organic fruits because these parameters are influenced also by fruit specie, cultivar, year and site of production. Combining isotopic and chemical markers a good discrimination between organic and conventional fruits of different species was achieved. © 2010 Elsevier Ltd.

Harrison S.M.,Agriculture and Food Science Center | Schmidt O.,Agriculture and Food Science Center | Moloney A.P.,Teagasc | Kelly S.D.,UK Environment Agency | And 5 more authors.
Food Chemistry | Year: 2011

Multiple stable isotope ratios (δ2H, δ13C, δ18O and δ34S) were measured in muscle, muscle lipids and lipid fractions collected from 28 lambs, subjected to a diet-switch and raised on two energy allowances (EAs), to determine tissue turnover and diet-tissue fractionation. The diet-muscle fractionations prior to the diet-switch were estimated to be -44.0‰, +1.9‰ and 0‰ for H, C and S, respectively, while the drinking water was demonstrated to be the main source of muscle O and thus δ18O variation. The diet-intra-muscular lipid fractionations prior to the diet-switch were estimated to be -172.7‰, -1.3‰ and -11.5‰ for H, C and O, respectively. The C half-lives of muscle were determined to be 75.7 and 91.6days for animals receiving the high and low EA, respectively. Extracting temporally resolved pre-slaughter dietary information from meat by analysing bulk muscle, muscle lipids and muscle lipid fractions appeared to be not practicable due to possible incomplete turnover of lipids. © 2010 Elsevier Ltd.

Schellenberg A.,Bayerisches Landesamt fur Gesundheit und Lebensmittelsicherheit | Chmielus S.,Bayerisches Landesamt fur Gesundheit und Lebensmittelsicherheit | Schlicht C.,Bayerisches Landesamt fur Gesundheit und Lebensmittelsicherheit | Camin F.,IASMA Fondazione Edmund Machinery | And 8 more authors.
Food Chemistry | Year: 2010

The aim of this study as a part of the food traceability project "TRACE" funded by the EU was to investigate if honeys produced in regions with different climatic and geological characteristics could be discriminated on the basis of the isotopic data. The hydrogen, carbon, nitrogen and sulphur stable isotope ratios of 516 authentic honeys from 20 European regions are presented and discussed. As honey contains only small quantities of nitrogen and sulphur, the honey protein was precipitated in order to obtain measurable amounts of these elements. The mean hydrogen isotopic ratios of the honey protein were found to be significantly correlated with the mean hydrogen isotopic ratios of precipitation and groundwater in the production regions. Carbon isotopic ratios were influenced by climate. The sulphur stable isotope composition is clearly influenced by geographical location (sea spray effect) and surface geology of the production regions. The results show that the stable isotope ratios of the four bio-elements carbon, nitrogen, hydrogen and sulphur in honey protein can be applied to verify the origin of honey. Carbon and sulphur were identified by canonical discriminant analysis as providing the maximum discrimination between honey samples. For seven regions the percentage of correct classified samples is greater than 70%. It was concluded that the methodology in its current state can be used to provide reliable origin information. © 2010 Elsevier Ltd. All rights reserved.

Tanz N.,Isolab GmbH | Tanz N.,TU Munich | Schmidt H.-L.,Isolab GmbH | Schmidt H.-L.,TU Munich
Journal of Agricultural and Food Chemistry | Year: 2010

The δ34S values of biological material, especially food commodities, serve as indicators for origin assignments. However, in the metabolism of higher plants sulfur isotope fractionations must be expected. As a matter of fact, the δ34S values of the sulfate- and organic-S, respectively, of Brassicaceae and Allium species vegetables showed differences between 3 and 6%o, and differences in glucosinolates were between 0 and 14%0. δ34S-value differences of total-S between individual tissues of the same plant were ∼3%0. It is believed that these relatively small and variable fractionations are due to the partition of individual S-metabolism steps to different plant compartments, where they may occur independently and quantitatively. The δ34S values of herbivore muscle meat and milk relative to the diet and between an animal and its child had trophic shifts of ∼1.5%0. 34S enrichments of up to 4%0 were observed for hair, hooves, and horn, an isotope fractionation of -5%0 between the diet sulfate and cartilage. Therefore, the reported agreements between δ34S value of biomass and primary S sources are true for only bulk material and not for individual compounds or tissues. © 2010 American Chemical Society Sulfur isotopes; isotope effects; isotope fractionations;δ34S values; origin assignment; glucosinolates; Brassicaceae; Allium species; animal tissues; organic-S; sulfate-S.

Rummel S.,Bavarian States Collection for Palaeontology and Geology | Hoelzl S.,Bavarian States Collection for Palaeontology and Geology | Horn P.,Bavarian States Collection for Palaeontology and Geology | Rossmann A.,Isolab GmbH | Schlicht C.,Bavarian Health and Food Safety Authority
Food Chemistry | Year: 2010

Within the EU-project "Pure Juice" established stable isotope methods (δ2H, δ13C, δ15N) have been applied and improved in order to determine and verify the geographical origin of orange juices. In addition, new approaches employing analyses of δ34S and 87Sr/86Sr have been developed and tested. Approximately 150 authentic orange juice samples from several regions in North- and South-America, Africa and Europe have been analysed. A discrimination of orange producing regions, based on the results which ultimately depend on geographical, climatic and lithological differences was successfully performed. Furthermore, we demonstrate that blending of single strength juice by adding concentrate can be revealed by comparing 87Sr/86Sr of soluble and insoluble components of the juices. We conclude that regional assignment of orange juice samples is most successful when single parameters are combined in a "multi-element approach". © 2008 Elsevier Ltd. All rights reserved.

Sieper H.-P.,Elementar Analysensysteme GmbH | Kupka H.-J.,Elementar Analysensysteme GmbH | Lange L.,Elementar Analysensysteme GmbH | Rossmann A.,Isolab GmbH | And 2 more authors.
Rapid Communications in Mass Spectrometry | Year: 2010

The quantitative conversion of organically bound oxygen into CO, a prerequisite for the 18O/ 16O analysis of organic compounds, is generally performed by high-temperature conversion in the presence of carbon at ~1450°C. Since this high-temperature procedure demands complicated and expensive equipment, a lower temperature method that could be utilized on standard elemental analyzers was evaluated. By substituting glassy carbon with carbon black, the conversion temperature could be reduced to 1170°C. However, regardless of the temperature, N-containing compounds yielded incorrect results, despite quantitative conversion of the bound oxygen into CO. We believe that the problems were partially caused by interfering gases produced by a secondary decomposition of N- and C-containing polymers formed during the decomposition of the analyte. In order to overcome the interference, we replaced the gas chromatographic (GC) separation of CO and N 2 by reversible CO adsorption, yielding the possibility of collecting and purifying the CO more efficiently. After CO collection, the interfering gases were vented by means of a specific stream diverter, thus preventing them from entering the trap and the mass spectrometer. Simultaneously, a make-up He flow was used to purge the gas-specific trap before the desorption of the CO and its subsequent mass spectrometric analysis. Furthermore, the formation of interfering gases was reduced by the use of polyethylene as an additive for analytes with a N:O ratio greater than 1. These methodological modifications to the thermal conversion of N-containing analytes, depending on their structure or O:N ratio, led to satisfactory results and showed that it was possible to optimize the conditions for their individual oxygen isotope ratio analysis, even at 1170°C. With these methodological modifications, correct and precise δ 18O results were obtained on N-containing analytes even at 1170°C. Differences from the expected standard values were below ±1‰ with standard deviations of the analysis <0.2‰. © 2010 John Wiley & Sons, Ltd.

Auerswald K.,TU Munich | Rossmann A.,Isolab GmbH | Schaufele R.,TU Munich | Schwertl M.,TU Munich | And 2 more authors.
Rapid Communications in Mass Spectrometry | Year: 2011

Stable isotope analysis of hair has found applications in many fields of science because it provides a temporally resolved, fairly stable isotopic archive of mammalian individuals. We investigated whether this hair archive is modified by natural weathering while attached to a living animal. We analyzed the tail switch hairs of one suckler cow, sampled seven times over a period of four annual summer pasture-winter stall feeding cycles. We compared relative isotope ratios (δ2H, δ13C, δ15N, δ18O and δ34S) of sections of hair that grew simultaneously but were exposed to natural weathering conditions over different periods of time. Natural wear caused a loss of mass of approx. 0.13% day-1, with no apparent effect of environmental conditions. Changes in δ2H, δ13C, δ15N and δ18O were below the detection limit, indicating that hair is a reliable archive for the isotopes of these elements. In contrast, δ34S values increased during the grazing period by about 1%, with exposure to UVradiation appearing to have a major influence on this result. The δ34S values decreased during the subsequent stall period, probably due to abrasion. Seasonal variation in δ34S may indicate alternating environments that differ in their weathering conditions. Copyright © 2011 John Wiley & Sons, Ltd.

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