A New Approach to the Analysis of Dissolved Gases Using Passive Samplers, With Portable Mass Spectrometry and Gas Chromatography Techniques

RATIONALE: Portable mass spectrometry systems such as miniRUEDI enable rapid and low-cost field analysis of dissolved gases with high temporal resolution. However, they remain poorly suited for discrete small-volume water samples. This study presents an approach based on passive sampling for groundwater and surface waters dissolved gases and gas tracer analyses. METHODS: Passive samplers (≈25 mL) were deployed in near-air-saturated water for several days to equilibrate with dissolved gases. After retrieval and locking, gas samples were analysed in the laboratory using the miniRUEDI portable mass spectrometry combined with gas chromatography-electron capture detection (GC-ECD). RESULTS: , CFC-12 and CFC-113 from a single 25 mL gas sample. The time required for complete equilibration within the passive samplers was found to be approximately 2 days. CONCLUSIONS: This method extends portable mass spectrometry to discrete low-volume water samples and facilitates the use of transient anthropogenic gas tracers for determining young groundwater ages (< 70 years). Its simplicity, low cost and multi-gas capability also make it promising for tracer plume mapping and environmental monitoring applications.