Compositions and methods for detection of target constituent in exhaled breath
Inventors
Lynn, Michael Scott • Tang, Hamilton Roger • Bechtel, Kate L. • Holst, Peter A.
Assignees
Triple Ring Technologies Inc • Hound Labs Inc
Publication Number
US-9921234-B1
Publication Date
2018-03-20
Expiration Date
2036-07-22
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
Chemical compositions and methods provide labeling, detection and measurement of target substances in exhaled human breath, and can be implemented in connection with a handheld device—much like a Breathalyzer portable breath testing unit for alcohol—to support rapid quantification of levels of cannabinoid compounds, such as tetrahydrocannabinol (THC), of suspected users at the roadside.
Core Innovation
The invention provides chemical compositions and methods for labeling, detecting, and measuring target substances in exhaled human breath. These methods can be implemented in connection with a handheld device similar to a Breathalyzer, enabling rapid quantification of cannabinoids such as tetrahydrocannabinol (THC) at roadside scenarios. The invention addresses the challenge of quantitative detection of THC in human breath, which is complicated by the low concentration of THC and the presence of chemical interferences.
A key aspect involves capturing an exhaled breath sample, forming a fluorescent-labeled sample adduct with THC in the sample, isolating and activating the fluorescent-labeled THC adduct, and detecting the amount of THC based on measured fluorescence. The process includes using suitable catch media for adsorption, elution with a first solvent, addition of a basic buffer and an aqueous diazotized fluorophore solution, separation into polar and nonpolar phases, and detection via fluorescent measurement. The method can be performed using a portable handheld device and allows for wireless transmission of data corresponding to detected THC levels.
The problem being addressed is that reliable detection of marijuana impairment through THC quantification is challenging due to the minute amounts of THC in breath, as opposed to alcohol. Existing blood or urine tests may lead to false positives since THC can remain in the body long after impairment. The system provides a convenient, non-invasive approach for rapid, accurate, and roadside measurement of THC in breath, overcoming limitations of current detection techniques.
Claims Coverage
There are three independent claims in this patent, each presenting a main inventive feature for the detection and analysis of THC in exhaled breath.
Method for detecting THC in exhaled breath using fluorescent labeling and solvent extraction
The method comprises: - Capturing THC from an exhaled breath sample by adsorption on a capture medium. - Collecting the captured THC in a capture solution by eluting with a first solvent. - Adding a basic buffer and a diazotized fluorophore solution to form a fluorescent-labeled THC adduct in a sample adduct solution. - Adding a second solvent, mixing, and separating the mixture into polar and nonpolar phases, with the nonpolar phase containing the fluorescent-labeled THC adduct. - Detecting THC by exposing the sample adduct in the nonpolar phase to a light source to produce fluorescence, measuring the fluorescence, and determining the quantity of THC based on the measured fluorescence.
Alternative method for detecting THC based on isolation and activation of a fluorescent-labeled adduct
This method includes: - Capturing an exhaled breath sample. - Forming a fluorescent-labeled sample adduct with THC in the captured breath sample in a sample adduct solution. - Isolating the fluorescent-labeled THC sample adduct from aqueous media. - Activating the fluorescent-labeled THC sample adduct fluorophore. - Detecting by determining the amount of THC in the captured breath sample based on the measured fluorescence of the isolated and activated fluorescent-labeled THC sample adduct.
Method for making a fluorescent-labeled THC-adduct using a primary amine-functionalized fluorophore
This method involves: - Combining a primary amine-functionalized fluorophore, sodium nitrite, and a diazo functional group stabilizer to form an aqueous solution of a diazo-functionalized fluorophore reactant with an acidic pH. - Forming a THC solution by dissolving THC in a polar organic solvent. - Buffering the THC solution by adding a basic buffer. - Combining the fluorophore reactant solution with the buffered THC solution to form a fluorescent-labeled THC-adduct solution, the adduct solution having a basic pH in the range of about 9-11.
The inventive features establish methods to detect THC in exhaled breath through sample capture, formation of a specific fluorescent-labeled adduct, its isolation and activation, and detection by optical means, as well as a process for the preparation of the relevant fluorescent-labeled THC adduct.
Stated Advantages
Supports rapid quantification of levels of cannabinoid compounds, such as THC, at roadside using a portable, handheld device.
Provides a convenient, non-invasive method for measuring THC in breath, which is widely accepted during roadside assessments.
Enables accurate detection and quantification of THC at very low concentrations in human breath, overcoming challenges of chemical interferences.
Avoids false positives associated with blood or urine testing for THC since these methods may detect THC long after impairment has ceased.
Documented Applications
Roadside detection and quantification of levels of cannabinoid compounds, such as THC, in exhaled breath of suspected users using a handheld device.
Simultaneous detection and quantification of multiple substances, such as THC and alcohol, from a breath sample taken using a handheld device.
Interested in licensing this patent?