Membrane-inlet mass spectrometry (MIMS)
Membrane-inlet mass spectrometry or MIMS measures dissolved gas concentrations of water samples. I use MIMS to measure primarily oxygen, nitrogen, and argon fluxes. By measuring the difference between actual dissolved gas concentrations and the predicted saturation values, we can calculate stream ecosystem production, respiration, nitrogen fixation, and denitrification. Along the way, I have figured out many things from processing the raw data from MIMS using R to designing sampling equipment. Listed here are some examples of things I have worked on regarding MIMS. Let me know if you have any suggestions!
Here is some information about the equipment I use to collect samples in the field and subtle modifications that can be done while running samples on the MIMS.
Bridget Deemer posted a helpful video of collecting a MIMS sample:
I wrote R scripts for converting the raw numbers from the MIMS readout into concentrations and ratios. The first file includes calculations for barometric pressure and saturated dissolved gas concentrations. Next, is an example of a spreadsheet for how to organize data for the calculations. Then is the R script that converts the raw MIMS numbers into concentrations and ratios. Finally, there is an example of what the ending datafile looks like after performing the calculations.