A microfluidic pH-stat with a specially-is designed slide and portable device can be used for point-of-care enzyme diagnostics. The slide includes a microchamber and a substrate for the enzyme being tested. The substrate is homogenized with the sample in the microchamber to form a test volume. The microchamber includes a working microelectrode that injects current to split water in the test volume to generate hydrogen ions and/or hydroxide ions and a micro-pH-electrode to measure a pH of the test volume; the slide also includes a reference microelectrode. The device includes a processor to adjust the injected current based on the pH of the test volume and determine an activity of the enzyme based on an amount the injected current is adjusted.

There is disclosed a nanopore support structure comprising a wall layer comprising walls defining a plurality of wells, and overhangs extending from the walls across each of the wells, the overhang defining an aperture configured to support a membrane suitable for insertion of a nanopore. There is further disclosed a nanopore sensing device comprising a nanopore support structure, and methods of manufacturing the nanopore support structure and the nanopore sensing device.

Device and methods for use in a biosensor comprising a multisite array of test sites, the device and methods being useful for modulating the binding interactions between a (biomolecular) probe or detection agent and an analyte of interest by modulating the pH or ionic gradient near the electrodes in such biosensor. An electrochemically active agent that is suitable for use in biological buffers for changing the pH of the biological buffers. Method for changing the pH of biological buffers using the electrochemically active agents. The methods of modulating the binding interactions provided in a biosensor, analytic methods for more accurately controlling and measuring the pH or ionic gradient near the electrodes in such biosensor, and analytic methods for more accurately measuring an analyte of interest in a biological sample.

An electrochemical electrode for use in a biosensor. The electrode comprises a substrate, a palladium metal layer manufactured on the substrate, and a palladium oxide-containing layer manufactured on the palladium metal layer. The palladium metal layer has a thickness of no more than 90 nm, and the palladium oxide-containing layer has a thickness of no more than 40 nm.

An electrochemical electrode for use in a biosensor. The electrode comprises a substrate, a palladium metal layer manufactured on the substrate, and a palladium oxide-containing layer manufactured on the palladium metal layer. The palladium metal layer has a thickness of no more than 90 nm, and the palladium oxide-containing layer has a thickness of no more than 40 nm.

An embodiment provides a method for deriving an amount of PFAS substances from a total organic fluoride measurement in a sample, including: removing inorganic fluoride from the sample using one or more of an ion exchange cartridge and an exclusion apparatus; preconcentrating, using a solid phase extraction, at least one PFAS substance in the sample; digesting, using a working electrode and a counter electrode, the at least one PFAS substance to an amount of total organic fluoride; and determining, using an analyzer, the amount of total organic fluoride in the sample. Other aspects are described and claimed.

Provided is a gas sensor element capable of realizing both highly accurate concentration measurement in environments where the concentration of a specific gas in a measurement target gas is high and highly accurate concentration measurement in environments where the concentration is low. A gas sensor according to one aspect of the present invention adjusts a sensor element drive temperature such that the value of cell resistance of a main pump cell is a predetermined value. Further, in the gas sensor according to one aspect of the present invention, the slope of the cell resistance of the main pump cell is larger than the slope of cell resistance of a measurement pump cell.

Provided is a gas sensor element capable of realizing both highly accurate concentration measurement in environments where the concentration of a specific gas in a measurement target gas is high and highly accurate concentration measurement in environments where the concentration is low. A gas sensor according to one aspect of the present invention adjusts a sensor element drive temperature such that the value of cell resistance of a main pump cell is a predetermined value. Further, in the gas sensor according to one aspect of the present invention, the slope of the cell resistance of the main pump cell is larger than the slope of cell resistance of a measurement pump cell.

A disposable self-sensing signal test strip includes a test strip body. The test strip body has a detection area and a circuit area. The detection area has a detection circuit. An electrochemical processing unit, a wireless transmission unit, and a power source unit are provided in the circuit area. The detection circuit is electrically connected to the electrochemical processing unit. The electrochemical processing unit sends to the detection circuit a control signal for performing detection. After receiving the control signal, the detection circuit reacts electrochemically with the test sample and sends a feedback signal to the electrochemical processing unit. The electrochemical processing unit converts the feedback signal into a detection parameter signal and sends the detection parameter signal through the wireless transmission unit to a receiving unit. The power source unit supplies electricity to the electrochemical processing unit and the wireless transmission unit.

A surface modified electrode is provided. The surface modified electrode includes a glassy carbon electrode (GCE) and a nanomaterial disposed on the glassy carbon electrode. The nanomaterial comprises carbon nanotubes (CNTs), and at least one of thallium oxide nanoparticles (Tl.sub.2O.sub.3.NPs), thallium oxide (Tl.sub.2O.sub.3) nanopowder, and thallium oxide carbon nanotube nanocomposites (Tl.sub.2O.sub.3.CNT NCs). A polymer matrix is configured to bind the glassy carbon electrode with the nanomaterial. A method of preparing the surface modified electrode is also disclosed. The surface modified electrode can be implemented in a biosensor for detecting a biological molecule, like choline.