Detection and measurement of target substance in exhaled breath
Inventors
Lynn, Michael Scott • Tang, Hamilton Roger • Dunk, Kevin Bradford • LIMTAO, Kevin M. • Jain, Hayuta
Assignees
Triple Ring Technologies Inc • Hound Labs Inc
Publication Number
US-11026596-B1
Publication Date
2021-06-08
Expiration Date
2038-05-16
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Abstract
Systems, techniques and compositions can detect and measure a target substance, such as THC, in a constituent sample from exhaled human breath.
Core Innovation
This invention presents systems, techniques, and compositions for detecting and measuring a target substance, specifically tetrahydrocannabinol (THC), in a constituent sample obtained from exhaled human breath. The invention includes analytical devices, methods, and reagents that allow for the collection of breath, formation of a fluorescent-labeled THC adduct, chemical activation of the adduct, and quantification of THC by measuring fluorescence in the adduct isolated in a nonpolar phase. These approaches employ luminescence-based detection, using a functionalized fluorophore that selectively forms an adduct with THC, which is then activated chemically to enhance optical signal detection.
The problem addressed is the lack of accurate, portable, and non-invasive devices for quantifying cannabinoid compounds, especially THC, in a person's breath, particularly for purposes such as roadside testing during suspected impaired driving. Existing challenges include the low concentrations of THC found in breath and the unreliability of blood or urine testing for recent use. Breath detection is described as a more reliable method to determine recent marijuana influence, as blood or urine samples may result in false positives for active impairment.
The system comprises a handheld breath capture device that collects a breath sample and adsorbs THC on a capture medium. The captured sample undergoes a series of reagent-based processing steps involving the addition of a basic buffer and an aqueous diazotized fluorophore solution to form a fluorescent-labeled THC adduct. Solvent extraction is then applied to isolate the adduct in a nonpolar phase, after which an acryloyl species—such as poly(2-ethyl hexyl acrylate)—serves as a liquid phase chemical activator to strengthen the fluorescence. The system includes an analysis unit with multiple fluidic and control components that automate reagent handling, mixing, activation, and optical analysis to determine the amount of THC present by fluorescence measurement.
Methods disclosed avoid complex immunological detection approaches by providing a robust chemical workflow involving selective binding of a functionalized fluorophore to THC, controlled activation to enhance optical response, and comparison to control samples for quantification. The invention further supports combined measurement of THC and ethanol from the same breath sample, providing the ability to simultaneously test for marijuana and alcohol use in a roadside setting.
Claims Coverage
The patent includes one independent claim, which defines a method for detecting THC in exhaled breath comprising several inventive features.
Processing exhaled breath to form a fluorescent-labeled THC sample adduct dissolved in a nonpolar phase
The method starts by receiving an exhaled breath sample from a breath capture device. The breath sample is processed so that any THC present forms a fluorescent-labeled THC sample adduct, which is dissolved in a nonpolar phase of an adduct solution.
Activation of fluorophore of THC adduct using a liquid phase chemical activator acryloyl species
A fluorophore in the fluorescent-labeled THC sample adduct is activated by adding a liquid phase chemical activator acryloyl species to the nonpolar phase. This step enhances the fluorescent response for subsequent detection.
Detection and quantification of THC based on measured fluorescence of the activated adduct in isolated nonpolar phase
Detection is accomplished by measuring the fluorescence of the activated fluorophore of the fluorescent-labeled THC sample adduct in the nonpolar phase, with the nonpolar phase being isolated from aqueous media. The measured fluorescence is used to determine the amount of THC in the breath sample.
In summary, the claims cover the complete workflow involving breath sample collection, formation of a fluorescently labeled and activated THC adduct in a nonpolar phase, and optical detection of THC by measuring the fluorescence of the isolated and activated adduct.
Stated Advantages
Enables accurate, portable, and non-invasive quantification of THC in exhaled breath.
Selective detection of THC avoids potential false positives encountered with blood or urine testing.
Provides a workflow that circumvents the need for complex immunological-based detection techniques.
Allows simultaneous measurement of THC and ethanol from a single breath sample.
Offers a luminescence-based approach that strengthens detection signal through chemical activation.
Facilitates convenient roadside testing, leveraging wide acceptance of breath tests.
Documented Applications
Quantification of THC (tetrahydrocannabinol) in exhaled human breath for purposes such as detecting marijuana use.
Roadside breath testing of impaired drivers for THC and ethanol using a portable analytical device.
Simultaneous detection and measurement of both THC and ethanol (alcohol) in the same human breath sample.
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