A fabricating method of a non-enzyme sensor element includes a printing step, a coating step and an electroplating step. In the printing step, a conductive material is printed on a surface of a substrate to form a working electrode, a reference electrode and an auxiliary electrode, and a porous carbon material is printed on the working electrode to form a porous carbon layer. In the coating step, a graphene film material is coated on the porous carbon layer of the working electrode to form a graphene layer. In the electroplating step, a metal is electroplated on the graphene layer by a pulse constant current to form a catalyst layer including a metal oxide.

According to one embodiment of the invention, an electrode evaluation method includes applying a voltage to an electrode with at least a part of the electrode including silver in contact with a liquid including an anion. The electrode evaluation method includes measuring a sheet resistance of the electrode after the applying.

An electrode includes a substrate film, an inorganic oxide layer, a metal underlying layer, and an electrically conductive carbon layer in order toward one side in a thickness direction.

The present invention relates to the technical field of glucose detection, and in particular to an enzyme-free glucose sensor and a fabrication method and use thereof. In the present invention, Magnolia grandiflora L. leaves are used as a carbon-based catalyst, which serve as a base material to well disperse nickel atoms and improve the catalytic activity of a material. A prepared Ni@NSiC nano-molecular layer is used to modify a pretreated white glassy carbon electrode (GCE) to obtain a highly-active material-modified working electrode Ni@NSiC/GCE, and then glucose is detected through cyclic voltammetry (CV) and chronoamperometry (CA).

Embodiments of the invention are directed to a system for detecting neurotransmitters. A non-limiting example of the system includes a porous electrode. A system can also include a pH sensor attached to the porous electrode, wherein the pH sensor includes a sensing electrode and a reference electrode. The system can also include electronic circuitry in communication with the pH sensor.

Provided are devices and methods for a rapid, non-perturbative and energy-efficient technique for pH sensing based on a flexible graphene electrode. This technique does not require the application of gate voltage or source-drain bias, and demonstrates fast pH-characterization with precision. The disclosed technology is suitable for in vivo monitoring of tumor-induced pH variation in tissues and detection of pH changes as required in a DNA sequencing system.

Methods, electrodes, and sensors for pH sensing using pseudo-graphite are disclosed. In one illustrative embodiment, a method may include coating a pseudo-graphite material onto a surface of an electrode substrate to produce a pseudo-graphite surface. The method may also include exposing the pseudo-graphite surface to a sample to measure a pH of the sample.

A carbon electrode includes a substrate, and a conductive carbon layer disposed at an upper side of the substrate and having an sp.sup.2 bond and an sp.sup.3 bond. On an upper surface of the conductive carbon layer, the concentration ratio of oxygen to carbon is 0.07 or more. The ratio of a number of sp.sup.3 bonded carbon atoms to the sum of a number of sp.sup.2 bonded carbon atoms and the number of sp.sup.3 bonded carbon atoms is 0.35 or more.

A sensor (20, 200, 1200, 30) for performing measurements is disclosed. It comprises: a substrate (29, 129, 39); a plurality of graphene field-effect transistors (GFET) (21, 121, 31) deposited on a central area of the substrate (29, 129, 39); at least one source electrode (22, 122, 32) connected to the GFETs (21, 121, 31) through at least one first metal track (23, 123, 33), wherein the at least one source electrode (22, 122, 32) is disposed at the periphery of the substrate (29, 39, 129); at least one drain electrode (24A-24C, 124A-124D, 34) connected to the GFETs (21, 121, 31) through at least one second metal track (25A-25C, 125A-125D, 35), wherein the at least one drain electrode (24A-24C, 124A-124D, 34) is disposed at the periphery of the substrate (29, 39, 129); and at least one gate electrode (26, 26B, 126A-126D, 36), disposed at least in part at the center of the substrate (29, 39, 129), wherein, in use of the sensor (20, 200, 30), when a sample is deposited in contact with the gate electrode (26, 26B, 126A-126D, 36) and the GFETs (21, 121, 31), the sample allows gating between the gate electrode (26, 26B, 126A-126D, 36) and the GFETs (21, 121, 31).

Method and system for detecting and/or quantifying Δ.sup.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.