Multiflow system for stable isotope analyses

点击翻译按钮获取中文摘要

The stable isotopes of carbon and oxygen in liquid, gas and solid compounds are tracers of biological and geochemical processes that are used for investigations in many disciplinary fields. The equipment (MultiFlow Geo) requested here is a gas extraction system to be coupled with an isotopic ratio mass spectrometer for the separation of CO2 from other gases and its introduction for measurements of low abundance carbon and oxygen isotopes. The equipment includes an autosampler that enables high throughput and unattended continuous analyses. It also includes an automated acid digestion unit for the recovery of CO2 from carbonates. The instrument optimizes operations and reduces measurement uncertainty compared to the current manually operated reaction vessels, allowing for sample sizes from less than 10 micrograms to milligrams and, thus, measurements of single shells of foraminifer (unicellular microorganism) as well as seasonal growth layers of teeth or stalagmites. The autosampler with temperature-controlled tray and gas separation system can process one sample every 3 minutes. Complementary kits will allow analyses of 1) hydrogen and oxygen isotopes in water for hydrology investigations, 2) carbon isotopes of dissolved inorganic carbon for studies of the carbon cycle, and 3) carbon and oxygen isotopes in breath CO2, for biomedical applications. The requested instrument will replace the current introduction system (MicroGas), acquired 22 years ago, that has generated more than 23 000 analyses over the last 15 years, for 25 university professors across Canada and 40 of their students. This old system cannot be configured to automatically inject acid nor flush reaction vials, nor run micro-samples. The proposed instrument would permit a large array of new experiments and research projects in addition to significantly enhancing the current throughput. It will complement the world-class light stable isotopes infrastructure of the Geotop research center in Earth system science, which has contributed to the training of more than 130 students, adding analytical support for the private sector. The main research projects of the applicant and co-applicants to be conducted with the instrument focus on a) the climate history and variations of sea ice cover in the Arctic Ocean, b) long-term ice-ocean-atmosphere interactions regulating the Earth climate, c) the seasonal climate contrasts and extremes in geological archives such as teeth of fossil mammals and cave stalagmites, d) the reconstruction of diets of prehistorical hominids in relation with climate, e) ocean acidification, and f) the renewal and quality of groundwater resources. In addition to the co-applicants of the present request, the equipment will be used by a large community of users from the private and academic sectors. On a yearly basis, about 20 students, several postdoctoral and visiting scholars will be trained for stable isotope measurements using the gas extraction system.