The RWI Noble Gas Lab is dedicated to the extraction, separation, purification and analysis of gas species obtained by out-diffusion from the porewater in the matrix of solid rock samples. Our focus lies on quantitative analysis of helium, neon and argon concentrations in the porewater as well as their isotopic compositions. A flexible separation and purification line geometry enables multiple aliquot analyses of samples with porewater noble gas concentrations spanning 5 orders of magnitude, allowing analysis of samples from ancient porewaters in crystalline rocks and porewater in sedimentary rocks. Additionally, reactive gas phases can be extracted to be measured by gas-chromatographic methods.
The analytical setup consists of an all-metal extraction line with a sequential combination of hot and cold getter pumps and liquid nitrogen cooled cryotraps. Measurements are obtained with a Pfeiffer QMS200 quadrupole mass spectrometer equipped with an in-line faraday cup detector operated in static mode. Analytical quality is monitored using reference gases such as pure air, pure noble gases and doped air, as well as by inter-laboratory comparison.