The article gives a condensed version of the keynote lecture held at the International Mass Spectrometry Conference 2012 in Kyoto. Starting with some examples for isotope research the key requirements for metrologically valid procedures enabling traceable and comparable isotope data are discussed. Of course multi-collector mass spectrometers are required which offer sufficiently high isotope ra...

The primary deuterium and tritium isotope effects on Vm/Km and on Vm have been measured for the O-deethylation of 7-ethoxycoumarin catalyzed by two purified isozymes of cytochrome P-450. From these data the intrinsic isotope effects have been calculated as described by D. B. Northrop (Biochemistry (1975) 14, 2644-2651). The observed deuterium isotope effects on Vm/Km are 3.79 and 1.90 for the i...

RATIONALE Dorsal white muscle is the standard tissue analysed in fish trophic studies using stable isotope analyses. However, sampling white muscle often implies the sacrifice of fish. Thus, we examined whether the non-lethal sampling of fin tissue can substitute muscle sampling in food web studies. METHODS Analysing muscle and fin δ(15)N and δ(13)C values of 466 European freshwater fish (14 ...

The degradation of organic micropollutants occurs via different reaction pathways. Compound specific isotope analysis is a valuable tool to identify such degradation pathways in different environmental systems. We propose a mechanism-based modeling approach that provides a quantitative framework to simultaneously evaluate concentration as well as bulk and position-specific multi-element isotope...

Whole-plant and leaf nitrogen isotope composition are determined by the isotope ratio of the external nitrogen source and physiological mechanisms within the plant. Whole-plant isotope composition can reflect that of the nitrogen source when plant demand exceeds nitrogen supply. Uptake by mycorrhizae can cause the isotope ratio of the plant to deviate from the source. Intra-plant variation in i...

PURPOSE Several isotopes are available for low dose-rate brachytherapy of the prostate. Currently, most implants use a single isotope. However, the use of dual-isotope implants may yield an advantageous combination of characteristics such as half-life and relative biological effectiveness. However, the use of dual-isotope implants complicates treatment planning and quality assurance. Do the ben...

Introduction: Evidence for isotope anomalies in primitive chondrites, and in iron meteorites, have been reported in Mo [1,2], Ru [3], Ba [4], Nd [5, 6], and Sm [6]. Osmium is a highly refractory element for which isotopic anomalies in bulk chondrites or differentiated meteorites have not been reported, yet. Brandon et al. [7] reported Os isotope anomalies in primitive chondrites, with the large...

introduction one of the first principles in the formation of a reserve is mineralogical, construction and mineral textures studies and investigation of paragenetic relations in the ore minerals. in addition, to petrographic studies, isotopic investigates have wide applications in economic geology. in general, copper isotope variability in primary (high temperature) mineralization forms a tight ...