Abstract: Hydrogen gas sensor and methods and systems using same to quantitate hydrogen gas and/or assess hydrogen gas purity. In one embodiment, the hydrogen gas sensor may include a planar, electrically non-conductive substrate. A working electrode, a reference electrode, a first counter electrode, and a second counter electrode may be positioned on a top surface of the substrate. The working electrode and the second counter electrode may be made of platinum, the first counter electrode may be made of ruthenium oxide, and the reference electrode may be made of silver chloride. The first counter electrode may have a surface area considerably greater than that of the working electrode. A proton exchange membrane may be deposited over the working electrode, the reference electrode, and the first and second counter electrodes. The electrodes and proton exchange membrane may be enclosed within a housing having an aperture to allow gas to enter for analysis.

Abstract: Method and system for detecting and/or quantifying ?9-tetrahydrocannibinol (THC) in exhaled breath. In one embodiment, the method involves providing an electrochemical sensing element, the electrochemical sensing element including a working electrode, and also providing a filter that traps THC in exhaled breath. Next, a subject exhales onto the filter, whereby at least some of the THC, if present, is trapped in the filter. Next, the filter is washed with an eluent, whereby at least some of the THC trapped in the filter is eluted in an eluate. Next, the eluate is deposited onto the working electrode of the electrochemical sensing element, and the eluate is dried, whereby any THC present is immobilized on the working electrode. Next, an electrolytic solution is delivered to the electrochemical sensing element, and the THC immobilized on the working electrode is directly electrochemically detected and/or quantified using a pulse voltammetry technique, such as square-wave voltammetry.

Abstract: Method and system for detecting drug and/or drug metabolites in a liquid sample, such as a wastewater sample. According to one embodiment, the method involves providing a device that includes a graphene field effect transistor and a first aptamer coupled to the graphene field effect transistor in a first well, the first aptamer being selective for a first drug or drug metabolite. Next, a liquid sample is introduced to the first aptamer of the device. Next, a sweeping liquid gate voltage is applied to the device to obtain a resistance versus liquid gate voltage plot for the device. Next, the Dirac voltage shift, if any, in the liquid gate voltage plot for the device is used to determine the presence and/or quantity of the drug or drug metabolite. Additional aptamers selective for different drugs or drug metabolites of interest may also be included in other wells of the device.

Abstract: Method and system for detection and quantification of oxidizable organics in water. The method involves the partial electrolytic decomposition of the oxidizable organics in a short time frame, preferably less than five seconds, and does not involve the use of toxic reagents. The system includes an electrochemical sensor probe that, in turn, includes a boron-doped diamond microelectrode array. The system additionally includes an electronic transducer and a computing device. The system utilizes an analysis technique to convert sensor signal to a result that can be correlated with COD or BOD values obtained by standard methods. The method and system are particularly suitable for, but not limited to, use in monitoring of water quality at wastewater treatment plants. By employing the method before and after adding aerobic microorganisms to the sample, the method may be used to distinguish biologically oxidizable organics from total oxidizable organics.

Abstract: Method and system for detecting and/or quantifying ?9-tetrahydrocannibinol (THC) in a saliva sample. In one embodiment, the method involves providing an electrochemical sensing element, the electrochemical sensing element including a working electrode, a counter electrode, and a reference electrode, all of which are screen-printed. A saliva sample is then deposited directly on the working electrode. Next, the deposited saliva sample is treated with a fluid that includes one or more alcohols and water in an alcohol/water ratio of 50/50 to 100/0 (v/v), the fluid optionally also including a surfactant. Next, the treated saliva sample is dried, whereby any THC present in the treated saliva sample is immobilized on the working electrode. Next, an electrolytic solution is delivered to the electrochemical sensing element, and the THC immobilized on the working electrode is directly electrochemically detected and/or quantified using a pulse voltammetry technique, such as square-wave voltammetry.

Abstract: Method and system for detecting and/or quantifying ?9-tetrahydrocannibinol (THC) in exhaled breath. In one embodiment, the method involves providing an electrochemical sensing element, the electrochemical sensing element including a working electrode, and also providing a filter that traps THC in exhaled breath. Next, a subject exhales onto the filter, whereby at least some of the THC, if present, is trapped in the filter. Next, the filter is washed with an eluent, whereby at least some of the THC trapped in the filter is eluted in an eluate. Next, the eluate is deposited onto the working electrode of the electrochemical sensing element, and the eluate is dried, whereby any THC present is immobilized on the working electrode. Next, an electrolytic solution is delivered to the electrochemical sensing element, and the THC immobilized on the working electrode is directly electrochemically detected and/or quantified using a pulse voltammetry technique, such as square-wave voltammetry.

Abstract: Method and system for detection and quantification of oxidizable organics in water. The method involves the partial electrolytic decomposition of the oxidizable organics in a short time frame, preferably less than five seconds, and does not involve the use of toxic reagents. The system includes an electrochemical sensor probe that, in turn, includes a boron-doped diamond microelectrode array. The system additionally includes an electronic transducer and a computing device. The system utilizes an analysis technique to convert sensor signal to a result that can be correlated with COD or BOD values obtained by standard methods. The method and system are particularly suitable for, but not limited to, use in monitoring of water quality at wastewater treatment plants. By employing the method before and after adding aerobic microorganisms to the sample, the method may be used to distinguish biologically oxidizable organics from total oxidizable organics.

Abstract: Method for electrochemically detecting different oxidant and halide anion species in a sample. According to one embodiment, the method uses a sensor including a boron-doped diamond working electrode, a platinum mesh counter electrode, a silver/silver chloride reference electrode, a potentiostat coupled to the three electrodes, and a computer coupled to the potentiostat. The sensor measures current resulting from differential pulse non-stripping voltammetry, thereby enabling different oxidants and halide anions from a plurality of such species to be detected by distinct responses. Peaks in the current signal result at characteristic voltages when a species is oxidized to a higher oxidation state, and the concentration of a particular species is determined by the magnitude of the current peak. The sensor response time is rapid and shows high sensitivity and selectivity for oxidants and halide anions. The sensor may be a hand-held or in-line device and may be used in a feedback-control system.

Abstract: A high-voltage electrochemical-electrolytic capacitor. The capacitor includes a cathode comprising a plurality of electrically-conductive particles in intimate electrical contact with one another and disposed in a proton-conductive, electrically-non-conductive, solid ionomer matrix. The capacitor also includes an anode comprising a plurality of electrically-conductive particles in intimate electrical contact with one another and disposed in a proton-conductive, electrically-non-conductive solid ionomer matrix, the electrically-conductive particles of the anode differing in composition from the electrically-conductive particles of said cathode. The capacitor further includes a proton-conducting dielectric positioned between and in contact with each of the cathode and the anode, the proton-conducting dielectric comprising a solid ionomer.