A device for measuring pH levels and contaminant concentration includes an electrode assembly that is electrically coupled to a control unit. The electrode assembly includes a FLUID first contact electrically coupled to a reference electrode, a second contact electrically coupled to a working electrode, and a third contact electrically coupled to a counter electrode. The working electrode may be modified to include a cysteine functionalized graphene oxide with polypyrrole nanocomposite. In operation, the control unit may apply a complex signal to the working electrode via the second contact in order to adhere and subsequently strip contaminant ions from the fluid sample to the working electrode. During this process, a current may be measured across the reference electrode and the counter electrode to measure contaminant ion concentration. The pH of the fluid sample may also be determined by a current measured across the reference electrode and the counter electrode. In some examples, the pH may be used to calibrate the measured levels of the contaminant ions.

A carbon nanotube-based reference electrode and an all-carbon nanotube microelectrode assembly for electrochemical sensing and specialized analytics are disclosed, along with methods of manufacture, and applications including detection of ionic species including heavy metals in municipal and environmental water, monitoring of steel corrosion in steel-reinforced concrete, and analysis of biological fluids.

The present disclosure describes a measuring system, comprising: a housing; a first chamber formed in the housing; arranged in the first chamber, a measuring cell, which includes a container embodied for receiving an electrolyte and at least one electrode for potentiometric and/or amperometric measurements, wherein the at least one electrode has a first section, which is arranged within the container, and a second section, which extends out from the container into the first chamber; and a temperature regulating apparatus, which is embodied to produce a temperature-controlled gas stream moving through the first chamber and flowing around the measuring cell, especially the container and the section of the at least one electrode extending from the container lid into the first chamber.

The invention relates to methods and apparatus for determining properties of a surface. Embodiments disclosed include an apparatus for measuring a surface charge of a sample, comprising: a sample holder having an opposed pair of electrodes and configured to hold a sample in position in a measurement volume between the electrodes such that a planar surface of the sample is aligned orthogonal to the electrode surfaces; a measurement chamber for containing a measurement liquid and having an open end configured to receive the sample holder to position the electrodes in a preset orientation; a laser light source positioned and configured to direct a laser beam through the measurement chamber between the electrodes and parallel to the planar surface of the sample when the sample holder is received in the measurement chamber; and a detector positioned and configured to detect scattered light from the measurement volume, wherein the apparatus is configured to allow for detection of the scattered light by the detector over a range of distances from the surface of the sample.

Composites comprising metal-oxide-functionalized carbon nanotubes with metal nanoparticles deposited thereon are provided. These composites can be used as a working electrode in an electrochemical sensor to detect arsenite in aqueous solutions. The composite can electrochemically reduce As.sup.3+ to As.sup.0 due to increasing adsorption capability. In one embodiment, Au nanoparticles are deposited on the TiOx/CNT electrode to facilitate the adsorption of As.sup.3+ on the electrode surface for further electrochemical reduction process. Square wave voltammetry (SWV) is performed to detect the electrochemical reduction of arsenite in water.

Disclosed are methods and devices for biomolecular detection, comprising a nanopipette, exemplified as a hollow inert, non-biological structure with a conical tip opening of nanoscale dimensions, suitable for holding an electrolyte solution which may contain an analyte such as a protein biomolecule to be detected as it is passed through the tip opening. Biomolecules are detected by specific reaction with peptide ligands chemically immobilized in the vicinity of the tip. Analytes which bind to the ligands cause a detectible change in ionic current. A sensitive detection circuit, using a feedback amplifier circuit, and alternating voltages is further disclosed. Detection of IL-10 at a concentration of 4 ng/ml is also disclosed, as is detection of VEGF.

Disclosed are methods and devices for biomolecular detection, comprising a nanopipette, exemplified as a hollow inert, non-biological structure with a conical tip opening of nanoscale dimensions, suitable for holding an electrolyte solution which may contain an analyte such as a protein biomolecule to be detected as it is passed through the tip opening. Biomolecules are detected by specific reaction with peptide ligands chemically immobilized in the vicinity of the tip. Analytes which bind to the ligands cause a detectible change in ionic current. A sensitive detection circuit, using a feedback amplifier circuit, and alternating voltages is further disclosed. Detection of IL-10 at a concentration of 4 ng/ml is also disclosed, as is detection of VEGF.

A sensor for the detection of lead includes a substrate, a working electrode formed on a surface of the substrate, a counter electrode formed on the surface of the substrate, a dielectric layer covering a portion of the working electrode and counter electrode and defining an aperture exposing other portions of the working electrode and counter electrode. The working electrode includes a metalized film with working surface and a monolayer (or bilayer) of bismuth deposited on the working surface by underpotential deposition.

A sensor for the detection of lead includes a substrate, a working electrode formed on a surface of the substrate, a counter electrode formed on the surface of the substrate, a dielectric layer covering a portion of the working electrode and counter electrode and defining an aperture exposing other portions of the working electrode and counter electrode. The working electrode includes a metalized film with working surface and a monolayer (or bilayer) of bismuth deposited on the working surface by underpotential deposition.

Shielded probe systems are disclosed herein. The shielded probe systems are configured to test a device under test (DUT) and include an enclosure that defines an enclosure volume, a translation stage with a stage surface, a substrate-supporting stack extending from the stage surface, an electrically conductive shielding structure, an isolation structure, and a thermal shielding structure. The substrate-supporting stack includes an electrically conductive support surface and a temperature-controlled chuck. The electrically conductive shielding structure defines a shielded volume. The isolation structure electrically isolates the electrically conductive shielding structure from the enclosure and from the translation stage. The thermal shielding structure extends within the enclosure volume and at least partially between the enclosure and the substrate-supporting stack.