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An advanced passive diffusion sampler for the determination of dissolved gas concentrations
Author(s) -
Gardner P.,
Solomon D. K.
Publication year - 2009
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2008wr007399
Subject(s) - aqueous solution , diffusion , volume (thermodynamics) , helium , gaseous diffusion , dissolved gas analysis , gas phase , chemistry , analytical chemistry (journal) , noble gas , dry gas , environmental chemistry , chromatography , thermodynamics , transformer oil , physics , organic chemistry , electrode , quantum mechanics , voltage , transformer
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.