Enhancing sampling of dissolved <scp>N₂O</scp> in aquatic systems: Field‐deployable automated gas bag collection system

Abstract Measuring dissolved nitrous oxide (N 2 O), a potent greenhouse gas and contributor to ozone depletion, is essential for understanding its aquatic dynamics and informing climate mitigation and emission estimates. Dissolved N 2 O concentration measurements typically involve headspace equilibration of water samples in sealed containers, followed by gas chromatography analysis. This manual method is labor‐intensive and often requires toxic preservatives. Alternatively, air‐water exchangers coupled with laser analyzers provide high‐precision continuous measurements but lack sample storage capabilities and require frequent relocation and setup to capture spatiotemporal variations. We developed an automated gas bag (AGB) collection system for collecting N 2 O samples (AGB‐N 2 O) from discrete water samples, which could then be analyzed for concentration using laser analyzers. This method combines the field‐friendly sample collection and storage of the manual method with the precision of exchangers and laser analyzers. Field experiments tested four setups of exchangers with varying internal volumes (2 L vs. 1 L) and water flow rates (small nozzle: 0.75 L min −1 vs. medium nozzle: 3 L min −1 ) at sites with low vs. high N 2 O concentrations (13 nM vs. 95 nM). The 2‐L exchanger with a medium nozzle achieved the fastest equilibration times of 2.25 and 0.08 min for high and low N 2 O sites, respectively. The AGB‐N 2 O showed comparable results to the manual method for measuring dissolved N 2 O concentrations ( p &gt; 0.05). However, the AGB‐N 2 O demonstrated significantly lower standard deviations, indicating higher precision and consistency. These findings demonstrate the suitability of the AGB‐N 2 O for diverse aquatic environments, offering reliable and efficient N 2 O measurements.