A quartz microbalance detector system for controlling the concentration of a gas component in a gas stream. The quartz microbalance interacts with the gas component, to effect a change in the oscillation frequency of the quartz microbalance detector and produce a signal correlative of concentration of...http://www.google.com/patents/US6156578?utm_source=gb-gplus-sharePatent US6156578 - Quartz crystal microbalance system for detecting concentration of a selected gas component in a multicomponent gas stream
