(TOP): Illustration of the working principle of the LGA system. (Bottom-left): Graph of a mass spectrum at a given time. (Bottom-right): A MS signal over time graph.

The LGA uses a coupled quadrupole mass spectrometer (QMS) to measure real-time concentrations of gasses and volatile species of fluids in, for instance, biogas fermentation or wastewater treatment tanks. The mass spectrometer works in a high vacuum to give precise measurements and therefore needs a membrane interface toward the liquid/gas environment. This is achieved in the LGA using our patented microchip design that controls the flow of molecules to the QMS. 

The mass spectrometer gives a signal value for each m/z ratio which, by knowing the flow of molecules, can be translated to a real-time concentration graph of, for instance, H2, CH4, NH3, N2, O2, H2S, N2O, NO2, EtOH, and light VFA’s (e.g., formic acid). Additionally, the mass spectrometer allows the user to add any additional compounds to be measured.