Developments

We are continuously trying to improve our ability to measure smallest possible samples for clumped isotopes. To this end, we use the Kiel device for sample preparation, dividing samples into aliquots of typically 80-100µg. Measurements are performed from the Kiel microvolume using the long integration-dual inlet (LIDI) approach, which maximizes the utilization of the sample gas. 

Due to non-linear instrument response and decreasing precision, low levels of humidity pose substantial challenges to stable isotope measurements in water vapour. In ambient conditions, this is particularly relevant in cold and dry conditions, such as the polar regions, with high-elevation polar regions such as Greenland and Antarctic ice caps being most challenging. Airborne measurements in polar and mid-latitude climates, but also subsidence regions are characterized by substantial changes in ambient humidity. At FARLAB, we develop and analyse new approaches to characterise the behaviour of Picarro isotope spectrometers at low humidity levels, develop calibration protocols, and assess the potential of hydrophobic silica coatings on tubing and instrument parts to improve instrument behaviour during low humidity conditions.