ADSORPTION GAS-FLOW MODULATOR FOR SENSITIVITY INCREASE OF MASS-SPECTROMETRIC MEASUREMENTS

A possibility for modulation of molecular flow through a capillary by its periodic heating and cooling has been investigated. The Knudsen ga s flow (when the length of the molecule free path is greater than the diameter of the capillary at variable temperatures of the capillary) a nd the Linear isotherm of adsorption have been analyzed in terms of di ffusion approximation. The analytical expression for the outlet flow h as been obtained for any given time dependence of the capillary temper ature and inlet flow. It has been demonstrated that such modulation ca n increase both sensitivity and selectivity of mass spectrometric meas urements and could be used for on-line analysis of gas streams.