An advanced passive diffusion sampler for the determination of dissolved gas concentrations

Abstract

[1] We have designed and tested a passive headspace sampler for the collection of noble gases that allows for the precise calculation of dissolved gas concentrations from measured gas mixing ratios. Gas permeable silicon tubing allows for gas exchange between the headspace in the sampler volume and the dissolved gases in the adjacent water. After reaching equilibrium, the aqueous-phase concentration is related to the headspace concentration by Henry's law. Gas exchange between the water and headspace can be shut off in situ, preserving the total dissolved gas pressure upon retrieval. Gas samples are then sealed in an all metal container, retaining even highly mobile helium. Dissolved noble gas concentrations measured in these diffusion samplers are in good agreement with traditional copper tube aqueous-phase samples. These significantly reduce the laboratory labor in extracting the gases from a water sample and provide a simple and robust method for collecting dissolved gas concentrations in a variety of aqueous environments.Citation: Gardner, P., and D. K. Solomon (2009), An advanced passive diffusion sampler for the determination of dissolved gas concentrations, Water Resour. Res., 45, W06423,

Use of Hydrochemistry, Stable Isotope, Radiocarbon, 222Rn and Terrigenic 4He to Study the Geochemical Processes and the Mode of Vertical Leakage to the Gambier Basin Tertiary Confined Sand Aquifer, South Australia

“…Noble gases were sampled without exposure to the atmosphere, using a passive diffusion sampler [30]. The sampler is about 15 cm in length and 3 cm in diameter.…”

“…The sampler was lowered into the well to a location at the midpoint of the well screen. Following the procedure described by Gardner and Solomon [30], samples were retrieved after 24 h of equilibrium in the well. 222 Rn was measured at the CSIRO Environmental Isotope Laboratory in Adelaide, using low-level liquid scintillation counting [31], and dissolved 4 He was analysed with a Stanford Research Systems RGA 220 quadrupole mass spectrometer with cryogenic separation (Poole et al [32], cited in Gardner et al [5]).…”

River infiltration to a subtropical alluvial aquifer inferred using multiple environmental tracers

“…Water for SF 6 analysis was pumped through a nylon tube into 1 L amber glass jars filled from the bottom and allowed to overflow for 5 min. For noble gases, equilibrium head space samples were collected using passive diffusion samplers [Gardner and Solomon, 2009]. Diffusion samplers were allowed to equilibrate with sample water (i.e., immersed in the piezometer at screen level or in the river) for 24 h, retrieved and clamped vacuum tight.…”

technical report and journal articles

“…Spalding and 4 Watson (2006) used silicon tubing attached to a syringe for sampling and direct injection of samples analyzed for H 2 , O 2 and CO 2 . Gardner and Solomon (2008) recently described a passive headspace diffusion sampler that maintains the total dissolved gas pressure. In cases where wells are not available or the specific yield of the formation is too small, rock samples have been collected and stored in evacuated stainless steel vessels.…”