Master Thesis Defense by Bettina Loy

Title: Tests investigating potential implementation of oxygen isotope measurements in continuous flow analyses

In addition to the current CFA setup at PICE, a line to measure oxygen isotopes was built. The gas separated from the ice cores flows through a membrane, where oxygen diffuses out and the O2 depleted sample gets measured in the mass spectrometer. This project aimed to create a second line for the extracted oxygen to be measured. Experiments were taken to investigate on the reaction time of the line and the permeation process of the membrane. Therefore, firn air bottles with different isotopic compositions were used to compare with the air in the lab. Permeation seems to be dependant on the volume of the wall and inner part of the membrane as well as the surrounding glass tube. While better measurements could be achieved with a thinner and shorter membrane, the results suggest that the membrane fractionates the oxygen to the point, where no difference in samples with varying delta values can be observed.

Supervisors: Thomas Blunier and Ida Lager (SLU)
Censor: Christian Juncher Jørgensen