Though the membrane inlet mass spectrometer (MIMS) has an established and long history with methane gas detection and analysis, primarily in microbiology, it is not commonplace in the environmental science community, which traditionally uses gas chromatography (GC). (However, an interesting aside is that there are now MIMS instruments being sent on autonomous underwater vehicles and down ship hydrowires to ‘sniff out’ methane and other dissolved compounds in both shallow and deep waters. — Bay Instruments MIMS, literally, don’t go there.) In the last few months, we’ve been to the ‘Sea’ near Charleston, South Carolina and a See’ (Lake) in Germany for instrument installations. Our Charleston host was Dr. Peter Lee at the Hollings Marine Laboratory and our Germany hosts were Drs. Hans-Peter Grossart and Danny Ionescu at the Leibniz Institute for Freshwater Ecology and Inland Fisheries on the Stechlinsee in Neuglobsow. What makes these two installations unusual and exciting for us is that the instruments will be used for methane gas analyses. Methane (CH4, mass 16) is a critical greenhouse gas with a heat-trapping potential ~20 times greater than carbon dioxide and there is great motivation to understand the sources and fates of methane in the environment. Even environments with only trace levels of methane can be important if they are large enough. Aquatic and marine systems can be significant local sources and the direct measurement of the dissolved gas can have some analytical advantages (such as avoidance of error associated with headspace equilibration). Standard practice is to analyze the fragment ion CH3+ (mass 15) to avoid atomic oxygen (mass 16) interference coming from oxygen gas and water vapor that are part of the gas stream. With our unique high precision inlet system, we are very interested in seeing how precise and sensitive our instrument is for this analyte (methane gas detection). We are looking forward to seeing the work that will come out of these two research groups.