Isotopic analysis of environmental samples using inductively coupled plasma mass spectrometry

• Main Author: Bazzano, Andrea
• Other Authors: Vanhaecke, Frank
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Genoa. Doctoral school of Chemical and Materials Sciences and Technologies 2016
• Subjects: Earth and Environmental Sciences; lead isotope ratios; micro samples; strontium isotope ratios; Antarctic atmosphere; Arctic pollution; Arctic; Antarctic; Svalbard; Antarc*
• Online Access: https://biblio.ugent.be/publication/7153939; http://hdl.handle.net/1854/LU-7153939; https://biblio.ugent.be/publication/7153939/file/7153947

In the context of environmental studies, isotope ratio measurements can help to discriminate between natural and anthropogenic inputs, as well as to identify their source regions and transport pathways. However, environmental samples can be characterised by a low amount of the target elements, thus hindering the measurement of precise and accurate isotope ratios. During this doctoral study, research activity was carried out taking into account both analytical and environmental aspects related to the determination of isotope ratios in environmental matrices. On the analytical side, much effort was focused on obtaining precise and accurate isotope ratios at low amount of the target element, using single-collector and multi-collector inductively coupled plasma mass spectrometry (ICP-MS). In particular, performances obtained measuring 208Pb/207Pb and 206Pb/ 207Pb ratios by single-collector ICP-MS at low sample consumption rates were investigated evaluating two micro-sample introduction systems: the PFA micro-nebuliser, working at 150 μL/min, and the torch integrated sample introduction system (TISIS), working at 20 μL/min. Under optimal conditions and using ammonia as damping gas, repeatability was 0.12 ± 0.03 and 0.17 ± 0.04 % RSD at 10 ng/mL of Pb, whereas the sample consumption was < 1.5 and 0.2 mL. TISIS was also coupled with multi-collector ICP-MS achieving a repeatability of 0.016 % consuming only 0.2 mL of sample solution. The coupling of the instrumental method with a pre-concentration step provided accurate ratios at Pb concentration levels down to 5 pg/g. Finally, the use of multi-collector ICP-MS with a membrane nebuliser desolvating system was also investigated for the measurement of precise and accurate 87Sr/86Sr ratios, obtaining an intermediate precision of 0.019 % at 0.4 ng/mL Sr concentration. The developed methods were largely applied to various environmental studies in the framework of PNRA (Italian National Program for Antarctic Research) and RIS (Research in Svalbard) projects. Indeed, Pb ...