Abstract: An improved ion mobility spectrometer (IMS) and method for operating the same which enables analysis of a specific acid gas analyte in a mixture of such gases when air is used as the carrier gas and the drift gas in the IMS. A controlled concentration of sulfur dioxide dopant is added to the air carrier gas stream prior to application of the carrier gas stream. In the IMS, the drift times of the ions generated from the doped air carrier gas differ from the drift times of the ions generated from the acid gas analyte, thereby enabling identification and quantification of the analyte.

Abstract: An ion mobility spectrometer, ionization detector and mass spectrometer is described having a reaction region, and a region for introducing a sample gas, liquid or solid samples into the reaction region and an electrolyte in the reaction region of an alkali salt heated to a predetermined temperature, such as room temperature to 1000.degree. C., to provide a chemical reaction between the alkali atoms, cations or complement anions with the sample to provide product ions. The invention provides a non-radioactive ionization source for ionization of a broad class of compounds.

Abstract: An improved method for operating an ion mobility spectrometer (IMS) to enable detection of an acid gas analyte when air is used as the carrier gas and the drift gas in the IMS. A controlled concentration of a dopant substance is added to the air carrier gas stream prior to application of the carrier gas stream. In the IMS, the drift times of the ions generated from the doped air carrier gas differ from the drift times of the ions generated from the acid gas analyte, enabling the identification and quantification of the analyte. The dopants comprise substituted phenol compounds, with methyl salicylate (MS) or 2-hydroxyacetophenone (2-HAP) being preferred.

Abstract: A method for operating an Ion Mobility Spectrometer in which an analyte sample is ionized in the spectrometer reaction chamber and the analyte ions are permitted to flow freely from the reaction chamber into the spectrometer drift chamber. The ion current output from the spectrometer ion current detector is observed during this time. The ion flow from the reaction chamber to the drift chamber is then momentarily interrupted and the time delay between the time of ion flow interruption and the appearance of a decrease in the ion current detector output is observed. Different substances are characterized by different delays. The concentrations of the different substances may be determined by measuring the change in detected ion current after the ion flow interruption.

Abstract: An ion mobility spectrometer, ionization detector and mass spectrometer is described having a reaction region, and means for introducing a sample gas, liquid or solid samples into the reaction region and an electrolyte in the reaction region of an alkali salt heated to a predetermined temperature, such as room temperature to 1000.degree. C., to provide a chemical reaction between the alkali atoms, cations or complement anions with the sample to provide product ions. The invention provides a non-radioactive ionization source and provides a means for ionization of a broad class of compounds.