Ion mobility spectrometry analyzer for detecting peroxides

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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application Nos. 60 / 952,669, filed Jul. 30, 2007, 60 / 953,879, filed Aug. 3, 2007, and 60 / 984,804 filed Nov. 2, 2007, each of which are hereby incorporated by reference in there entirety to the extent not inconsistent with the disclosure herein.BACKGROUND OF INVENTION[0002]Recent developments in ion mobility spectrometry have made this technique a widely applicable and powerful analytical tool for detection and characterization of a broad class of molecules. Ion mobility spectrometric analysis provides one of the most universally applicable analysis methods, as it is applicable to almost any species capable of forming an ion in the gas phase. In addition, ion mobility spectrometry methods provide highly selective and sensitive detection (e.g., parts per trillion for some species). Accordingly, these methods are especially attractive for quantitative analysis...

AI Technical Summary

Benefits of technology

[0012]The present invention provides IMS analyzers and methods for detecting, identifying, and characterizing (e.g., measuring the concentration of) peroxides in samples. In an embodiment, methods and systems of the present invention utilize dopant strategies, and optionally sample inlet conditions, providing an enhancement in selectivity and sensitivity for the detection of peroxide analytes relative to conventional IMS analyzers. 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. Methods and systems of the invention also are capable of accurate peroxide measurements over a large effective dynamic range. Systems and methods of some aspects, for example, provide detection and characterization peroxides over a concentration range at low as a few parts per billion (ppb) to a high as 1000's of parts per million (ppm), and are capable of real time detection and characterization of peroxides with fast response times on the order of milliseconds for some sampling conditions. Methods and systems of the present invention are also capable of accurate and stable calibration, optionally via an automated, on board calibration system.

[0013]In an aspect, the present IMS peroxide detection systems and methods provide enhanced sensitivity and selectivity by minimizing, or entirely eliminating, sources of interference arising from background ions generated from carrier gases, drift gases and / or impurities present in a sample. A number of strategies are useful in the present invention for suppressing interference from ions generated from water vapor such as: (i) use of a sample introduction interface providing preferential transport of peroxides into the system relative to water vapor, (ii) addition of dopant(s) to the system capable of modifying the drift times of potentially interfering ions away from those of peroxide analyte ions via charge transfer, charge scavenging, complex formation and / or cluster formation reactions, and (iii) addition of dopant(s) to the system capable of modifying the drift times of peroxide analyte ions away from those of potentially interfering ions via charge transfer, complex formation and / or cluster formation reactions. In an embodiment of the present invention, dopant provided to the analyzer scavenges electrical charge from interfering ions generated from water vapor in the analyzer. IMS methods and analyzers of some embodiments use a combination of sample introduction via a selectively permeable hydrophobic membrane and the addition of specific dopant(s) to achieve sampling and ionization conditions that effectively suppress interfering IMS signals corresponding to ions derived from water vapor in the sample. Ionization and detection conditions accessed by this aspect of the invention, therefore, provide a distinctive IMS signal(s) corresponding to peroxide analyte(s) that is easily identified, quantified and distinguished from IMS signals corresponding to other ions derived from water vapor and / or other impurities in the system. This feature of the present invention is particularly beneficial for detection and sensing applications in environments having a significant water component, such as monitoring of peroxides during aseptic processing, ambient air monitoring, and in homeland security applications for detection of peroxide-based explosives and / or precursors of peroxide-based explosives. This feature of the present invention is also useful for enhancing sensitivity and selectivity in IMS analyzers using air as a carrier gas and / or drift gas given the significant and variable concentrations of water vapor commonly present in air.

Problems solved by technology

This source of inference may result in false positive readings that degrade overall performance, and is particularly significant for applications involving the identification and detection of analytes present in a sample at low concentrations.

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