Abstract: A gas analysis apparatus including a sorption bed and a receiver normally spaced apart from the sorption bed. A given flow path is defined between the sorption bed and the receiver for directing a gas to be analyzed across the sorption bed for adsorption thereby in an adsorption mode of operation of the apparatus. A drive relatively moves the sorption bed and the receiver closer together from their spaced apart condition to produce a volume reduction of the defined, given flow path across the sorption bed in a desorption mode of operation of the apparatus. A heater selectively heats the sorption bed to desorb the adsorbed gas from the bed into the volume reduced flow path. A gas analyzer is connected to the receiver for analyzing the desorbed gas.