Abstract: The present invention provides IMS analyzers and methods for detecting, identifying, and characterizing (e.g., measuring the concentration of) peroxides in samples. Methods and systems of the present invention utilize sample inlet conditions and dopant strategies providing an enhancement in selectivity and sensitivity for the detection of peroxide compounds relative to conventional IMS analyzers. Dopants of the present invention include, but are not limited to, substituted aryl compounds or substituted cyclic dienes; wherein the substituted aryl compound or the substituted cyclic diene has at least one substituent selected from the group consisting of a hydroxyl group, a carbonyl group, an aldehyde group, an ester group, a carboxylic acid group and a carbonate ester group. The present IMS analyzers and methods are versatile and enable selective detection of a broad class of peroxides and derivatives thereof, including hydrogen peroxide, hydroperoxides, organic peroxides and derivatives thereof.

Abstract: An improved ion mobility spectrometer (IMS) and method for operating the same which enables analysis of chlorine dioxide in a mixture of gases which also includes the interferant chlorine. A controlled concentration of an amine such as methylamine is added to the air carrier gas stream prior to application of the carrier gas stream. The amine suppresses the chlorine peak, thereby improving the specificity of the IMS to chlorine dioxide. The IMS of the present invention also includes an improved membrane filter for pre-filtering chlorine, and a software algorithm for accommodating peak drift.

Abstract: An improved ion mobility spectrometer (IMS) and method for operating the same which enables analysis of ammonia in a mixture of gases when air is used as the carrier gas and the drift gas in the IMS. A controlled concentration of an ester such as Dimethyl methyl phosphonate (DMMP) is added to the air carrier gas stream prior to application of the carrier gas stream. The DMMP clusters with the ammonia, and the drift times of the ionized clusters differ from the drift times of the ions generated from the other constituents of the sample, thereby enabling identification and quantification of the ammonia.

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 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: An ion mobility spectrometer is described incorporating an air mixer having a clean air inlet and a sample air inlet, an ion mobility spectrometer cell for generating reaction ions and sample ions which are subsequently measured in a drift region, a first circuit for measuring the reactant ion peak and the sample ion peak, a second circuit for generating a feedback control signal to the air mixer in response to the reactant ion peak and a third circuit for generating a signal indicative of concentration of the sample molecules in sample air at the inlet utilizing the sample ion peak and the feedback control signal to the air mixer. The invention overcomes the problem of limited dynamic range due to saturation of the ion mobility spectrometer cell.