VALVED SAMPLING CELL FOR MEMBRANE INTRODUCTION MASS-SPECTROMETRY

Membrane extractors comprising a membrane house inside of a valve have been developed to separate compounds of interest from a sample matrix and introduce these compounds into a mass spectrometer. Experimental control over parameters that affect permeability or that may damage. t he membrane, such as the membrane temperature, is provided with the va lve. The valve was tested for response and response times with the val ve separated from the mass spectrometer by various interface tube leng ths. Data for steady state response measurements showed no significant change With the valve at different distances from the ion source, Pol ar compounds show a strong response time dependency on the interface t ube length, This adsorption phenomenon is minimized by simply heating the interface tube, Other factors affecting the performance of the dev ice are discussed.