According to various implementations, an apparatus for electromagnetic impedance spectrographic characterization of a material under test (MUT) includes: a planar array of at least two electrodes configured to be placed in electromagnetic communication with the MUT, wherein during operation of the planar array, at least one of the electrodes comprises a transmitting electrode for transmitting an electromagnetic signal over a range of frequencies through the MUT to at least one receiving electrode in the planar array; and a backer ground plate at least partially surrounding the at least two electrodes, the backer ground plate being electrically grounded and insulated from the at least two electrodes, wherein the backer ground plate extends from a plane formed by the at least two electrodes and separates the at least two electrodes to create an electrically isolated volume proximate to the at least two electrodes.

Described systems and methods allow the detection and quantitation of a target analyte such as a toxin, drug, pesticide, etc. Some embodiments use a sensor comprising photo-sensitive cells, e.g., cells genetically modified to express an opsin. A light source such as an LED is used to optically stimulate the sensor cells, triggering changes in a measurable quantity such as the polarization of the cell membrane. Some embodiments use electrical impedance measurements to monitor the cell's recovery from the state induced by the optical stimulation. The recovery process is affected by the presence of certain bio-active compounds, which allows detection and quantitation of such compounds.

Various implementations include systems and approaches for measuring an electromagnetic impedance characteristic of a fluid under test (FUT) in a fluid channel. In some cases, a system includes: a transmitting electrode assembly including: a transmitting electrode having a transmitting surface; and a transmitting electrode backer ground plate at least partially surrounding the transmitting electrode; a receiving electrode assembly including: a receiving electrode having a receiving surface; and a receiving electrode backer ground plate at least partially surrounding the receiving electrode, where the transmitting electrode and the receiving electrode are located in a set of walls defining the fluid channel, the transmitting surface and the receiving surface each conform to a shape of the set of walls defining the fluid channel, where the fluid channel permits transverse flow of the FUT relative to both the transmitting electrode and the receiving electrode.

An apparatus for identifying and measuring volume fraction constituents of a fluid using time domain analysis and frequency domain analysis to identify individual volume fraction constituents within a pipe on a real time basis and to measure the volume of the individual volume fraction constituents flowing through the pipe on a real time basis.

A method for identifying and measuring volume fraction constituents of a fluid using time domain analysis and frequency domain analysis to identify individual volume fraction constituents within a pipe on a real time basis and to measure the volume of the individual volume fraction constituents flowing through the pipe on a real time basis.

Methods for detecting one or more analytes in a sample utilizing Electrochemical Impedance Spectroscopy (EIS) measurement. In one method, analyte detection includes comparing an imaginary impedance measurement to a calibration curve of concentrations for each target analyte. The calibration curve of concentrations for each target analyte is established at an optimal frequency. In another method, a signal decoupling algorithm is utilized for detection of more than one analyte on an electrode.

The present invention related to a technique for determining the progesterone-associated physiological state of a lactating cow. The technique comprises determining at least one Milk Solid (MS)-related parameter in at least one milk sample from a lactating cow; and determining the progesterone-associated physiological state according to the Milk Solid (MS)-related parameter. Determining the progesterone-associated physiological state may comprise determining the progesterone level of the cow by correlating the MS-related parameter with calibrated data. The MS related parameter may comprise at least one of size, synthesis, composition of a MS, a pattern of progesterone concentration or direction of progesterone concentration, or at least one dielectric parameter of the MS.

A sensor system includes a multi-frequency sensor assembly including a single sensor body housing with a sensing region circuit and a sensor reader disposed in the sensor body. The sensor body is configured to be in operational contact with a fluid. The sensing region circuit is configured to generate different electric fields having different frequencies in the fluid. The sensor reader includes one or more processors configured to examine one or more impedance responses of the sensing region circuit at different frequencies and to determine one or more properties of the fluid based on the one or more impedance responses that are examined.

A monolithic gas-sensing chip assembly for sensing a gas analyte includes a sensing material to detect the gas analyte, a sensing system including a resistor-capacitor electrical circuit, and a heating element. A sensing circuit measures an electrical response of the sensing system to an alternating electrical current applied to the sensing system at (a) one or more different frequencies, or (b) one or more different resistor-capacitor configurations of the system. One or more processors control a low detection range of the system to the gas, a high detection range of the system to the gas, a linearity of a response of the system to the gas, a dynamic range of measurements of the gas by the system, a rejection of interfering gas analytes by the system, a correction for aging or poisoning of the system, or a rejection of ambient interferences that may affect the electrical response of the system.

The invention is directed to a chemically robust, highly-selective, low power sensor that can be used for the direct electrical detection of mixed gases. In particular, metal-organic frameworks (MOFs) offer exceptional chemical and structural tunability as mixed-gas capture materials. As an example of the invention, the influence of interfering gases on trace NO.sub.2 detection in a simulated flue gas stream was investigated. The unique interaction of NO.sub.2 with the MOF's metal center leads to orders of magnitude decrease in MOF resistance. More broadly, the coadsorption of specific gases (e.g., H.sub.2O, SO.sub.2) can be beneficial to the electrical detection of the target gas (e.g., NO.sub.2), and careful electrical measurements can discern their presence independent of the target gas.