Quartz resonator based gas mass spectrometry

A mass spectrometry gas sensing method using tuning fork crystal quartz resonator was investigated. Resonant frequencies and quality factors of 32.768kHz and 40.000kHz resonators were measured in nine different gases (H₂, He, C₂H₂, 4%H₂+ 96%N₂, N₂, Air, O₂, Ar and SF₆) at 296K and 1 atm. Resonant frequencies f₀ and quality factors Q of the resonators decreased as a function of molecular mass of the gas as expected from gas theory. The linear relationship between f₀ and molecular mass can be utilized as a gas sensing method, with sensitivity of 0.236Hz/g/mol. General gas sensing designs have been put forward using gas filtering membranes, Knudsen compressor and MEMS quartz resonators.