Abstract: A filter for a mass- or mobility-spectrometer that bars gases or vapors of a high-pressure ion source, as well as ions of high mobility and charged droplets, from entering an evacuated mass spectrometer or a mobility spectrometer at a lower pressure than the filter. The buffer gas of the high pressure ion source is blown into the volume of this filter directly or through tubes from where buffer gas and embedded ions are sucked through the aperture of a diaphragm or through an aperture of a capillary mainly from an “extraction volume” filled with a separately supplied clean gas, into which ions of interest are pushed by electric fields formed by electrodes that are substantially rotational symmetric around the “extraction volume” and a substantially flat electrode with respect to an axis of ion extraction and the end of the capillary and the end of a coaxial tube surrounding the capillary.

Abstract: A filter for a mass- or mobility-spectrometer that bars gases or vapors of a high-pressure ion source, as well as ions of high mobility and charged droplets, from entering an evacuated mass spectrometer or a mobility spectrometer at a lower pressure than the filter. The buffer gas of the high pressure ion source is blown into the volume of this filter directly or through tubes from where buffer gas and embedded ions are sucked through the aperture of a diaphragm or through an aperture of a capillary mainly from an “extraction volume” filled with a separately supplied clean gas, into which ions of interest are pushed by electric fields formed by electrodes that are substantially rotational symmetric around the “extraction volume” and a substantially flat electrode with respect to an axis of ion extraction and the end of the capillary and the end of a coaxial tube surrounding the capillary.

Abstract: Generally, the present invention provides a recirculating filtration system for use with a transportable ion mobility spectrometer in gas chromatography applications. The transportable recirculating filtration system comprises a pump and a set of filters and flow sensors connected to an ion mobility spectrometry sensor having a gas chromatograph column at its inlet. The IMS sensor's outlet flow is cleaned by the filters and recirculated by the pump back into the IMS sensor as the carrier fluid stream flow. A portion of the IMS sensor's outlet flow equal to the amount of flow introduced into the sensor as the sample is exhausted from the filtration system to maintain a constant total flow volume through the system as the sample is being analyzed. Preferably, the multicapillary column is sealed to a heated transfer line leading to the sample stream inlet of the IMS sensor. The transfer line is preferably maintained at a temperature 10.degree. C.-40.degree. C.