a water management system removes water vapor from the analyte slug that is desorbed from the trap . the water management system includes a device having a passage through which the volatile organic chemicals and water pass , the passage being designed to remove water vapor by swirling action on the stream . the amount of water removed is more than can be accounted for by simple condensation . the invention also includes the adjustment of the temperature of the water management device during the sample concentration cycle to prevent undesired condensation prior to desorption .