Pumping-induced ebullition: a unified and simplified method for measuring multiple dissolved gases.

Area of Science:

• Environmental Science
• Geochemistry
• Analytical Chemistry

Background:

• Measuring multiple dissolved gases in natural waters is complex and costly.
• Existing methods require separate sampling procedures for each gas.
• Incompatibilities in sample handling lead to inaccuracies and biogenic gas alteration.

Purpose of the Study:

• Introduce pumping-induced ebullition (PIE) as a unified approach for dissolved gas measurement.
• Establish PIE as a platform for in situ, real-time dissolved gas monitoring.
• Demonstrate PIE's application in analyzing major, trace, and ultratrace dissolved gases.

Main Methods:

• PIE induces ebullition by pumping water through a narrow tube, reducing pressure below saturation.
• Buoyancy traps evolved gas bubbles in a collection tower for accumulation.
• Unified gas samples are collected for multiple chemical analyses.

Main Results:

• PIE enabled accurate and precise measurement of diverse dissolved gases (N2, O2, Ar, CO2, N2O, CH4, CFCs, SF6) in Wisconsin groundwater.
• The method revealed interrelationships between denitrification, recharge age, and land use.
• PIE eliminated multiple sampling methods, simplified analysis, and prevented gas alteration during storage.

Conclusions:

• PIE offers a unified, efficient, and accurate method for routine dissolved gas analysis in natural waters.
• The technique facilitates the development of in situ real-time monitoring tools.
• Further research is needed to investigate gas departures from solubility equilibrium.