The subject of this thesis is water with increased abundances of the rare stable isotopes 2H and 18O (and to some extent also 17O). Such artificially enriched (or "labelled") waters are often used in biomedicine, for establishing the total amount of body water (and thus body composition) of humans and animals and also for measuring their energy expenditure. These non-evasive totally harmless techniques offer great advantages, however they require accurate and precise "isotope ratio" measurements as well as reliable reference waters for calibration.
In the thesis a prototype optical (so-called OF-CEAS) instrument for more sensitive and precise measurements of the three isotope ratios in isotope-labelled water is described. Furthermore, the production and certification of two sets of labelled reference waters is documented. These sets of waters are now established as international reference materials for biomedical research and as such distributed by the International Atomic Energy Agency (IAEA).
Another, very different use of these isotope-labelled waters lies in the realm of thermometry. The SI unit of temperature, the Kelvin, is defined using the temperature of the so-called triple point of water (in which all three phases, solid, liquid and vapour, coexist). The triple point temperature, however, depends on the isotopic composition of the water used. We performed an exact quantification of isotope effects on this triple point temperature by measuring this temperature for a series of differently, and well-known isotope-labelled waters. We performed these measurements in collaboration with the National Dutch Measurement Institute VSL. Our work has lead to both a general higher quality of temperature measurement, and to a more accurate realization of the Kelvin according to the SI definition.
Leonardo Arriagada Beltran conducted his PhD research on the interface of computer-generated art and the constantly evolving field of Artificial Intelligence (AI). He will defend his Phd thesis on 21 September. His research offers valuable insights...
Harish Vedantham and Casper van der Kooi have been nominated by New Scientist for Wetenschapstalent 2023 (Science Talent 2023). This election is meant to give young scientists and their research a stage.
No less than five promising PhD graduates from the University of Groningen will be able to conduct research at top institutes abroad for two years thanks to the Rubicon programme organized by the Netherlands Organisation for Scientific Research...
The UG website uses functional and anonymous analytics cookies. Please answer the question of whether you want to accept
or reject other cookies (such as tracking cookies).
If no choice is made, only basic cookies will be stored. More information