Noble gases are useful in analyzing physical processes in the environment such as air-sea gas exchange and sea ice formation and melting. Traditional measurements of noble gases are costly and time-consuming because of the need to transport water samples to analyze in a laboratory-based mass spectrometer. Field deployable mass spectrometers were developed as a low-cost method to increase the temporal resolution of the measurements. Our system utilizes a quadrupole mass spectrometer in tandem with a gas equilibrator cartridge to continuously measure equilibrated gases from water with ambient air as a calibration standard. The reproducibility of the system is better than 0.7% and the accuracy is better than 0.9% for all gas ratios in a lab environment. However, our current configuration is not optimized for measuring helium because of the high permeability of helium through many materials. Measuring helium will yield insight into quantifying bubble processes, which significantly affects rates of air-sea gas exchange. Our mass spectrometer configuration was thus extended to measure helium by switching from fused silica capillaries to stainless steel capillaries. The precision and accuracy of the gas ratios in the new configuration will be accessed and compared to values prior to modification of the system. This project seeks to improve the spatial and temporal resolution of noble gas measurements, including helium, from field-deployable mass spectrometers to an accuracy and precision that will enable it to be useful for<br/>gas exchange studies.

Adapting a field-deployable mass spectrometer for continuous measurements of helium

255th National Meeting (2018)

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