[en] Although the existence of atomic complexes and/or complex ions in the vacuum spark, and also the consequent difficulties often encountered in trace analysis by spark source mass spectrometry (SSMS), have been known for a long time, neither the processes of formation nor the properties of these complexes have yet been satisfactorily investigated. The physical and chemical processes taking place in various gas ion sources have in most cases been thoroughly investigated and the results obtained used not only to improve the analytical performance, but also to acquire information about the processes themselves. Similar investigations of the spark ion source are highly desirable too, and may be successful if based on the advantageous features of the SSMS method (relatively high resolving power, considerable sensitivity), and on isotope ratio measurements instead of the less reproducible elemental analyses. A study of the processes in the spark by using stable isotope tracers obviously seemed to be a promising undertaking. First, a study of the formation of aluminium oxide complexes was begun (with ¹⁸O as tracer) and later the investigation was extended, by using electrodes containing Sm₂O₃ and SmCl₃ with ¹⁴⁴Sm as the tracer. Results are given and discussed. (author)

[en] The subject is discussed under the headings: mass spectrometric measurements; isotope dilution analysis of halides; chloride and bromide trace analysis. (U.K.)

[en] A description is given of the determination of the isotope ratios of carbon isotopes, using a static mass spectrometer; some of the limitations involved are outlined; and areas are indicated where advances and improvements are expected in the future. The subject is discussed under the headings: multiplier effects; gas degradation effects. (U.K.)

[en] The subject is discussed under the headings: general; ionization efficiencies; multielement analysis; isotope analysis of an americium and curium mixture; isotope analysis of a mixture of thorium, uranium and plutonium; direct burn-up analysis by isotope dilution mass spectrometry; isotope analysis of a caesium and barium mixture. (U.K.)

[en] The increased lead concentrations in the atmosphere are to be attributed particularly to the combustion of gasoline containing organic lead components as antiknock additives. Furthermore, the operation of smelters and coal burning electric power plants can be important as pollutant sources. Since each natural lead deposit has a characteristic isotopic composition the knowledge of this composition can make it possible to differentiate between the various sources of emission. The isotopes ²⁰⁶Pb, ²⁰⁷Pb and ²⁰⁸Pb are continuously created as the end-products of radioactive decay of uranium and thorium. In contrast to that the isotope ²⁰⁴Pb is not known to have been formed by any radioactive decay process. The present-day lead isotope ratios are, therefore, a function of the parent uranium-thorium abundances and the age of the systems. In order to identify the lead emitted by coal burning electric power plants the isotopic composition of lead in various West German pit coals was determined by mass spectrometry. The procedure is described, and the results are given and discussed. (author)

[en] The subject is discussed under the headings: exchange reactions (between mixtures of H₂, D₂, T₂ in the gaseous phase); mass spectrum (table of ions produced; steps in the calculation of quantitative results); calibration of mass spectrometer; experimental results; error calculations. (U.K.)

[en] Kinetic deuterium isotope effects on mass spectral reactions have in several instances been utilized to provide structural information and to answer mechanistic questions. Typically, the influence of the deuterium label on the rate of one of a number of competing reactions has been studied. Secondary isotope effects have usually been assumed to be relatively insignificant in comparison with the observed kinetic effects, even though various workers have shown that secondary isotope effects may indeed exert a considerable influence on the rates of competing simple cleavages. Recent studies have provided quantitative data to show that the mere presence of deuterium atoms up to six bonds away may influence the rate of a simple cleavage reaction. In relation to an investigation of rearrangements accompanying simple cleavage reactions, a semi-quantitative measure was needed of the variation of the secondary isotope effect with the number of bonds between the deuterium label and the point of rupture. The influence has therefore been examined of the presence of remote deuterium atoms on a typical simple cleavage reaction, the α-cleavage of aliphatic amines. As a model compound, N-methyldipentylamine was chosen, systematically labelled with deuterium. (author)

[en] Aluminium 26 is one of the extinct nuclides. It decays to ²⁶Mg with the half life of 7.2 x 10⁵ yr. In order to confirm whether ²⁶Al existed in the early solar system or not, magnesium isotopic abundance anomalies have been examined in some chondrites and terrestrial rocks by many investigators. In the present work point-to-point (SIMS) analyses of Mg isotopic anomalies were carried out for the Allende inclusions and matrix with an accuracy of about 3 parts per thousand. They were compared with that for the terrestrial forsterite sample. The results are presented and discussed. (author)