Simultaneous Analysis of Noble Gases, Sulfur Hexafluoride, and Other Dissolved Gases in Water

Abstract

We developed an analytical method for the simultaneous measurement of dissolved He, Ne, Ar, Kr, Xe, SF6, N2, and O2 concentrations in a single water sample. The gases are extracted from the water using a head space technique and are transferred into a vacuum system for purification and separation into different fractions using a series of cold traps. Helium is analyzed using a quadrupole mass spectrometer (QMS). The remaining gas species are analyzed using a gas chromatograph equipped with a mass spectrometer (GC-MS) for analysis of Ne, Ar, Kr, Xe, N2, and O2 and an electron capture detector (GC-ECD) for SF6 analysis. Standard errors of the gas concentrations are approximately 8% for He and 2-5% for the remaining gas species. The method can be extended to also measure concentrations of chlorofluorocarbons (CFCs). Tests of the method in Lake Lucerne (Switzerland) showed that dissolved gas concentrations agree with measurements from other methods and concentrations of air saturated water. In a small artificial pond, we observed systematic gas supersaturations, which seem to be linked to adsorption of solar irradiation in the pond and to water circulation through a gravel bed.

Insight into chemical, biological, and physical processes in coastal waters from dissolved oxygen and inert gas tracers

“…The accuracy is similar to (Brennwald et al, 2013a;Sano and Takahata, 2005;Beyerle et al, 2000) or somewhat less accurate than (Stanley et al, 2009a;Hamme and Severinghaus, 2007) laboratory-based methods that cause much higher cost and labor. Additionally, the laboratory-based methods with higher precision require much more expensive instrumentation (over 250 000 USD), have higher analysis costs (∼500 USD per sample), and have lower sample throughput (∼4 samples per day), since each sample takes several hours to extract and analyze.…”

Development of the portable mass spectrometer and its application in environmental monitoring

“…However, the sample compositions may change due to the influence of pressure, temperature or other conditions in the process of sampling and transportation, which is difficult to ensure the accuracy and effectiveness of environment contamination analysis. Rapid qualitative and accurate quantification of pollutants in the field is a critical problem that needs to be solved all the time [1][2][3]. In recent years, portable mass spectrometers have attracted wide attention due to their high sensitivity, fast analysis and wide application [4][5][6].…”

Conquering the Outdoors with On-site Mass Spectrometry

“…This approach is limited to the sequential analysis of individual water samples that were taken in special airtight containers. [28][29][30][31][32][33][34] However, the concentrations of O 2 and noble gases dissolved in groundwater may exhibit a high degree of variability, both spatially and temporally. [14,21,[35][36][37] For instance, groundwater in the vicinity of a losing river is most likely prone to the same dynamics as the stream water itself with respect to its chemical composition.…”

“…1 C, valves V1 and V2), because the partial pressures of O 2 , N 2 , and the noble gases in the atmosphere are stable and known. [32] Furthermore, the concentrations of atmospheric noble gases in groundwater and surface water are often similar to their respective concentrations in air-saturated water. The composition of noble gases in the EC is therefore often similar to that in the atmosphere.…”