The document discusses several topics related to gas analysis using mass spectrometry, including: 1) Mass spectrometry provides greater sensitivity for detecting trace gases compared to other methods. It can also distinguish between biogenic and thermogenic gases based on differences in associated gas levels. 2) Examples from a field study show mass spectrometry detected slight decreases in water, nitrogen, argon and oxygen indicating thermogenic gas, as well as identifying disconformities, salt welds and pressurized shale zones. 3) The document discusses performing lag checks and washout calculations with the mass spectrometer to quality control the instrument's performance.