The invention provides a multi-layered electrode for sensing pH, the electrode comprising: a sensing layer on a substrate, the sensing layer comprising at least one proton-sensitive metal oxide, wherein a pH-dependent potential of the multi-layered electrode is measurable via an electrically conductive connection to the sensing layer; a proton-permeable layer covering at least a portion of the sensing layer, the proton-permeable layer comprising at least one electrically insulating proton-conductive metal oxide; and a carbonaceous layer on the proton-permeable layer, the carbonaceous layer comprising amorphous carbon.

A pH sensor device, intended to be inserted into the ground in order to be in contact with a region containing a fluid from the ground, for which fluid the pH is desired to be known, comprising: a pH sensor comprising a surface covered in a polymer material configured to be in contact with the region containing a fluid when the device is inserted into the ground, a metal element having a surface configured to be in contact with the region containing the fluid when the device is inserted into the ground, electrical connection means connected at least to the metal element and configured to receive a cathodic-protection electrical potential for the metal element.

The invention also relates to a method for measuring pH that can be used for cathodic protection.

The invention disclosed herein relates to a dry sensor for measuring the concentration of an analyte in a liquid beverage sample. Described herein is a novel dry sensor which is able to receive a liquid sample and adjust the pH of the liquid to be suitable for assaying an analyte of interest without the need to add reagents to the sample and/or to perform manually timed operations and able to detect a redox reaction in the presence of a liquid sample. The meter disclosed herein, when connected to the sensor disclosed herein is able to adjust the temperature of the liquid to be suitable for the assay, apply a series of potentials, measure the current at several times, measure the diffusion coefficient of the limiting electrochemical species, calculate the concentration of one or more analytes, and rapidly provide the user with the required information on the liquid sample.

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.

A sensor arrangement includes a storage chamber comprising an interior space, containing a liquid, with an opening, a reference terminal lead which contacts liquid and can be connected to a superordinate unit, and a sensor tube comprising a sensitive region for detecting a measured quantity of the measuring medium and a measuring terminal lead. The sensitive region can be electrically connected to the superordinate unit. The sensor tube can be moved from a first position into a second position. The sensitive region is located in the interior space of the storage chamber in a first position and outside the storage chamber in the second position. The storage chamber, the opening, and the sensor tube, in the first position, are configured such that the reference/storage/calibration liquid is prevented from escaping from the interior space, and, in the second position, configured such a liquid transport is formed.

The present invention relates generally to systems for measuring pH. In particular, the present invention relates to a continuous flow system having one or more solid state pH sensors positioned within a fluid pathway of the system to provide continuous pH measurement.

Various apparatus, systems, and methods for measuring a solution characteristic of a sample comprising microorganisms are disclosed. In one embodiment, a sensor apparatus is disclosed comprising a sample container comprising a sample chamber configured to receive the sample and a reference sensor component comprising a reference conduit having a reference conduit cavity defined therein. The reference conduit cavity can be at least partially filled with a reference buffer gel, buffer solution, or wicking component. A segment of the reference conduit can extend into the sample chamber. A reference electrode material can be positioned at a proximal end of the wicking component or extend partially into the reference conduit cavity. The sensor apparatus can also comprise an active sensor component having an active electrode in fluid contact with the sample. The sample in the sample chamber can be aerated through an aeration port defined along a surface of the sample container.

Apparatus and methods are provided for measuring phosphate in water. The methods can involve electrically pre-treating a potentiometric sensor and using the electrically pre-treated potentiometric sensor in a water sample to obtain a phosphate measurement. The potentiometric sensor includes a working electrode and a counter electrode. The working electrode includes a metal/metal oxide electrode having a detection surface. The electrical pre-treatment generates a metal phosphate on the detection surface of the metal/metal oxide electrode. The phosphate measurement results in a fresh layer of mixed oxide on the detection surface of the metal/metal oxide electrode. The electrically pre-treatment can be performed in situ in the water sample, allowing for field monitoring of water bodies. In some embodiments, the method can also involve cleaning the sensor prior to electrically pre-treating the sensor or after obtaining the phosphate measurement.

An embodiment provides a method for compensating for inteferants in measurement of alkalinity in a reagent-less system, including: introducing an aqueous sample into a measurement device comprising one or more series of electrodes; applying an electrical signal to the aqueous sample using the one or more series of electrodes, wherein the electrical signal is selected from the group consisting of: current and voltage; identifying, during application of the electrical signal, that the electrical signal reaches an oxidation threshold and measuring, prior to reaching the oxidation threshold, a first electrical response to the electrical signal, the first electrical response attributable to interferants in the aqueous sample; identifying, during application of the electrical signal, that the electrical signal reaches an endpoint and measuring, from the oxidation threshold to the endpoint, a second electrical response to the electrical signal; and measuring an alkalinity of the aqueous sample based upon a difference between the first electrical response and the second electrical response. Other aspects are described and claimed.

A sensor for measuring a pH value of a measuring liquid includes: a sensor element including a surface adapted to the measuring liquid; a radiation source configured to emit electromagnetic transmission radiation to the sensor element, wherein at least a portion of the transmission radiation is converted into measurement radiation by reflection and/or scattering in a region of the surface; a radiation receiver configured to receive the measurement radiation and convert it into electrical signals; and a measuring circuit configured to determine the pH value from signals, wherein a wavelength of at least a portion of the transmission radiation generates charge carriers in at least a surface region or a near-surface region of the surface of the sensor element as to effect a photoelectrochemical reaction with formation of hydrogen at the surface.