Detection of peroxide radicals and reaction initiators
Inventors
Lock, John • Geraghty, Edward • Kagumba, Lawino • Rice, Norm • Higginson, Keith • Mahmud, Ken • Gavrin, Arthur
Assignees
Publication Number
US-8778271-B2
Publication Date
2014-07-15
Expiration Date
2029-05-21
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Abstract
Sensors for the detection of free radicals and free radical forming compounds including, for example, peroxides, as well as energetic radiation, UV light, plasma or heat each such sensor including a functional component are described herein. In addition, this disclosure includes methods for making such sensors and methods for using sensors including a functional component and devices incorporating such sensors.
Core Innovation
The invention is directed to sensors and detection methods for free radicals and free radical forming compounds, such as peroxides, as well as initiators induced by energetic radiation, UV light, plasma or heat. Each sensor contains a functional component comprising reactive groups that exhibit a distinct change in polymerization state—such as crosslinking, uncrosslinking, polymerization, or depolymerization—when contacted by targeted initiators. The sensors further comprise a sensing element, at least one surface of which is coated with the functional component, and a detector capable of sensing the polymerization state of these reactive groups.
Existing microcantilever-based sensors largely rely on detecting analyte adsorption through changes in mass, resonance frequency, or bending, but lack specificity and selectivity for free radical detection, particularly for peroxides and related initiators. The invention addresses this problem by employing tailored functional components, such as self-assembled monolayers with specific head and reactive groups, which undergo amplification via chemical amplification upon initiation by trace radical presence, thereby providing both heightened sensitivity and selectivity.
In operation, the sensors can detect specific reaction initiators, including peroxide radicals, by facilitating a self-amplified polymerization or crosslinking reaction upon interaction with radicals or trigger energy. This reaction is monitored by various detector types, capable of measuring changes in capacitance, frequency, resistance, surface energy, refractive index, or physical deflection of cantilever elements. The functional components can be structured for reversibility or irreversibility, enabling the detection of both transient and persistent radical species using formats ranging from microcantilever-based chips to portable, bench top, or walk-through devices.
Claims Coverage
The patent contains a principal independent claim covering the sensor for detecting reaction initiators, detailing its main inventive elements.
Sensor featuring a self-assembled monolayer functional component with reversible polymerizable reactive groups sensitive to free radicals
A sensor includes: - A functional component that comprises a plurality of reversibly polymerizable reactive groups, capable of exhibiting a change in state of polymerization when contacted by free radicals. - A sensing element with an upper and lower surface, at least one of which is coated with a self-assembled monolayer of the functional component. - At least one detector fixedly attached to the sensing element, which is capable of detecting the polymerization state of the reactive groups of the functional component by measuring a change in capacitance of the sensing element caused by polymerization.
The inventive feature centers on integrating a surface-bound, self-assembled monolayer with reversibly polymerizable reactive groups and a detector that senses the polymerization response to free radicals, capturing the core mechanism of highly selective and sensitive initiator detection.
Stated Advantages
Sensors exhibit increased sensitivity and selectivity due to self-amplified chemical reaction initiated by free radical or peroxide radical.
Multiple peroxide radicals generated from each peroxide-containing molecule enhance detection sensitivity and selectivity.
The design reduces the number of false positives by specifically detecting peroxide radicals which are unlikely to be formed by non-peroxide compounds.
Microcantilever-based sensors provide inherent sensitivity, and the amplified polymerization response enables detection of minute amounts of reactive compounds.
The approach allows for reversible or regeneratable detection, supporting the monitoring of transient or persistent radical species.
Documented Applications
Detection of peroxide-containing compounds, azo-containing compounds, and persulfate-containing compounds in liquid, vapor, or solid states.
Devices can be configured as hand held, bench top, stand alone, or walk-through systems for various settings including chemical laboratories, storage facilities, and airport security screening.
Integration into bomb detecting devices, including detection of explosives such as triacetone triperoxide (TATP), hexamethylene triperoxide diamine (HMTD), and their constituent components like hydrogen peroxide.
Auxiliary component for walk-through detectors for explosives, metal, or radiation, adding peroxide detection to pre-existing security infrastructure.
Continuous area monitoring for peroxide-containing compounds in environments such as laboratories, storage facilities, or vehicles using peroxide-based fuels.
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