Determination of thallium in brain tissue by stable isotope dilution and field desorption mass spectrometry.

Quantitative investigations on the diaplacental transfer of thallium by field desorption mass spectrometry.

The placental transfer of thallium cations in pregnant mice was investigated by determining the thallium concentrations in fetal and maternal tissue 0.5 to 24 h after application of thallium. The maternal dose of thallium was 8 mg/kg body weight throughout. Uterus and fetus were found not to differ from other organs like heart and liver in time course and magnitude of thallium uptake with an in...

Evaluation of minimal 13C-labelling for stable isotope dilution in organic analysis.

A procedure for Stable Isotope Dilution Analysis in molecular Mass Spectrometry which does not require a methodological calibration graph and can be applied in combination with minimal labelling has been evaluated. This alternative approach is based on the determination of the molar fractions for each pure isotope pattern (natural abundance or labelled) contributing to the isotope pattern obser...

Fragmentation of the a-Amino Acid Methionine in Field Desorption Mass Spectrometry

H.-R. Schulten and W. D. Lehmann Institute of Physical Chemistry, University of Bonn, Wegeierstraße 12, D-5300 Bonn Z. Naturforsch. 83 b, 770-781 (1978); received March 21, 1978 Field Desorption Mass Spectrometry, a-Amino Acid Methionine The fragmentation of methionine in field desorption mass spectrometry has been studied. Decomposition mechanisms are described which are based on stable isotop...

Determination of selenium in biological materials by stable isotope dilution gas chromatography-mass spectrometry.

Uncertainty calculation on the determination of calcium absorption in nutritional experiments with enriched stable isotopes and detection by double focusing sector field ICP-MS with a shielded torch

A new method for the measurement of calcium isotope ratios and total calcium, using a double focusing sector field inductively coupled plasma mass spectrometry (ICP-MS) instrument equipped with a shielded torch, is presented. The method was applied for the measurement of the Ca/Ca, Ca/Ca and Ca/Ca ratios and total calcium by isotope dilution in urine samples from two different nutritional exper...