Further progress was made with the method during a project undertaken by the company to study the changes in daily energy expenditure with ageing in humans, the results of which were published in the Science journal of the American Association for the Advancement of Science in August.
The study involved the provision of the stable isotope of oxygen-18 to selected participants, as required by the “doubly labelled water method” used during the research. The isotope is also needed for stable isotope analysis in biological samples such as blood, urine and saliva, part of the company’s development of a “gold standard” for measuring total energy expenditure.
Oxygen-18 enrichment plant.
Source: Taiyo Nippon Sanso
With all three isotopes of oxygen in air – 16, 17, and 18 – being nearly identical in terms of physico-chemical properties, enrichment and separation is considered extremely difficult. By harnessing its oxygen-18 enrichment method using O2 cryogenic separation technology, TNSC managed to obtain the world’s highest enrichment level of over 98atom% (considered ‘high enrichment’).
Beginning its production in 2004, TNSC currently produce 600kg of water-18O (oxygen-18 enriched water) across its three oxygen-18 production plants per year. Water-18O has multiple uses across the medical industry including in Positron Emission Tomography (PET) cancer diagnosis, an effective method of early-stage cancer diagnosis and prognosis and as a raw material in the testing of Alzheimer’s disease.
The full Science journal study by TNSC is available to read here.