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Isotope Ratio Measurements of Biological Systems

Carbon isotope fractionation effects of individual compounds were observed in living organisms and also as a result of enzymatic isotope effects and reaction kinetics in biological systems. Such fractionation effects have to be examined by isotope ratio mass spectrometry in order to understand specific processes in life sciences or in environment.75 [Pg.331]

Actinides found as environmental contamination in mosses collected from a bog in the eastern Italian Alps were analyzed after their chemical separation by extraction chromatography (deposited on steel targets) with respect to isotope ratios and their concentration was determined by LA-ICP-MS. Moss samples were contaminated with a variety of actinide isotopes. The detection limits for actinides were determined as 3.6-7.2 x 10 gg for Am and respectively. The Pu/ Pu isotope ratio (0.212 0.003) was almost constant within experimental error for all samples investigated. Pu contamination in moss samples was mainly the result of global fallout after nuclear weapons tests. Am was found at the 2x 10 gg level. This example demonstrates that mosses can be used as bioindicators for environmental contamination.  [Pg.331]

Isotope ratio measurements were employed for the quantification of analytical data using the isotope dilution strategy. For example, isotope dilution analysis was developed by Sanz-Medel s group for the determination of selenomethionine in Se enriched yeast material by HPLC-ICP-MS using a Se-enriched selenomethionine spike obtained by growing yeast on a Se rich culture medium. For Cr(III)/Cr(VI) determination in yeast, Caruso et al employed the double spike species specific isotope dilution technique measured by HPLC-ICP-MS. The isotope pattern deconvolution approach applied in this work delivers a more intuitive and elegant solution to an otherwise complex data analysis without the need for iterative calculations as widely practised in double spike isotope dilution. The results are in exact agreement with the conventional isotope dilution calculations.  [Pg.331]

5 Trace and Imaging Analysis on Biological Tissnes and Single Cells [Pg.333]

An emerging field in bioanalytics is the direct analysis of tissues to study the lateral distribution of elements, element species or biomolecules. Over the past few years, the development [Pg.333]


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