6078 results about "Detection limit" patented technology

This document describes an optical sensor unit and a procedure for the specific detection and identification of biomolecules at high sensitivity in real fluids and tissue homogenates. High detection limits are reached by the combination of i) label-free integrated optical detection of molecular interactions, ii) the use of specific bioconstituents for sensitive detection and iii) planar optical transducer surfaces appropriately engineered for suppression of non-specific binding, internal referencing and calibration. Applications include the detection of prion proteins and identification of those biomolecules which non-covalently interact with surface immobilized prion proteins and are intrinsically involved in the cause of prion related disease.

A Selective Catalytic Reduction (SCR) catalyst was prepared by slurry coating ZSM-5 zeolite onto a cordierite monolith, then subliming an iron salt onto the zeolite, calcining the monolith, and then dipping the monolith either into an aqueous solution of manganese nitrate and cerium nitrate and then calcining, or by similar treatment with separate solutions of manganese nitrate and cerium nitrate. The supported catalyst containing iron, manganese, and cerium showed 80 percent conversion at 113 degrees Celsius of a feed gas containing nitrogen oxides having 4 parts NO to one part NO₂, about one equivalent ammonia, and excess oxygen; conversion improved to 94 percent at 147 degrees Celsius. N₂O was not detected (detection limit: 0.6 percent N₂O).

Disclosed is a lateral flow quantitative assay method which can measure one or more analyte species at the same time, with high sensitivity. Also, the present invention relates to a strip which can measure one or more analyte species at the same time, with high sensitivity and a package in which the strip is integrated with a laser-induced surface fluorescence detector. The present invention can quantify multiple analytes with a minimum detection limit of pg/ml. Therefore, the present invention provides an advantage capable of quantifying a plurality of analytes at the same time using a simple lateral flow assay strip.

The present invention provides a class of sensors prepared from at least a first material having a positive temperature coefficient of resistance and a second non-conductive or insulating material compositionally different than the first material that show an increase sensitivity detection limit for polar and non-polar analytes. The sensors have applications in the detection of analytes in the environment, associated with diseases and microorganisms.

A method for detecting one or more target bacteria in a raw sample where: 1) bacteriophage(s) specific to each target bacterium are added to the raw sample, 2) the test sample is incubated, and 3) the test sample is tested for the presence of each phage in sufficient numbers to indicate the presence of the associated target bacteria in the raw sample. In one embodiment, each phage is initially added to the raw sample in concentrations below the detection limit of the final phage detection process. In another embodiment, the parent phages are tagged in such a way that they can be separated from the progeny phage prior to the detection process. Preferred phage detection processes are immunoassay methods utilizing antibodies that bind specifically to each phage. Antibodies can be used that bind to the protein capsid of the phage. Alternatively, the phage can by dissociated after the incubation process and the sample tested for the presence of individual capsid proteins or phage nucleic acids. The invention can be used to test target bacteria for antibiotic resistance.

A novel surface plasmon resonance (SPR) imaging system based on modified Mach-Zehnder phase-shifting interferometry (PSI) measures the spatial phase variation of a resonantly reflected light during chemical or biological detection. The SPR microarray can diagnose the target analyte without additional labeling in the real-time analysis. Experimental results demonstrate that the detection limit of the SPR PSI imaging system is improved to about 1 pg/mm<2 >surface coverage of chemical or biological material for each individual spot over that of the conventional SPR imaging system. Therefore, the SPR PSI imaging system and its SPR microarray can provide the capability of real-time analysis, with high resolution and at high-throughput screening rates.

Compact tunable optical cavities are provided for in-situ NIR spectroscopy. MEMS-tunable VCSEL platforms represents a solid foundation for a new class of compact, sensitive and fiber compatible sensors for fieldable, real-time, multiplexed gas detection systems. Detection limits for gases with NIR cross-sections such as O₂, CH₄, CO_x and NO_x have been predicted to approximately span from 10^ths to 10s of parts per million. Exemplary oxygen detection design and a process for 760 nm continuously tunable VCSELS is provided. This technology enables in-situ self-calibrating platforms with adaptive monitoring by exploiting Photonic FPGAs.

A spectrometry method and apparatus for filtering step-like pulses output by a preamplifier to measure the energy or other desired characteristics of events occurring in a detector attached to the preamplifier. The spectrometer provides a set of filters that are capable of measuring the desired characteristic with different accuracy or resolution, detects the pulses in the preamplifier signal, and measures the time between consecutive pairs of detected pulses. For each detected pulse, the spectrometer selects a filter from the set of available filters, based on the measured time intervals between the pulse and its immediately preceding and succeeding detected pulses, applies it to the pulse, and indexes the output of the filtering operation with one or more indices identifying the selected filter.

A new generation polarimetry apparatus and methodology is disclosed, which involve passing polarized light through a sample including a chiral analyte, where the analyte is under the influence of a periodically varying magnetic field. The apparatus also utilizes optical heterodyne detection and lock-in detection at higher order harmonics of the magnetic field modulation frequency to improve sensitivity and detection limits of optical properties of chiral analytes.

The invention relates to a detection method, in particular to a rapid detection method employing ultrasensitive quantum dot microsphere immunity-chromatograph test paper strips. The prior art has the disadvantage that the detection sensitivity is unable to satisfy demands of users because of high detection limit of samples, complex composition of the samples and great pretreatment difficulty. The rapid detection method of the invention comprises the steps of: preparing silicon dioxide nanoparticles, incubating the amino silicon dioxide nanoparticles with antibody for 1-10 hours in the presence of a condensation agent at 37 DEG C, and removing the antibody and the condensation agent which are failed to bond 1-4 times through high-speed centrifugation, redissolving precipitates obtained after centrifugation, adding the condensation agent and carboxylic water-soluble quantum dots, and removing free quantum dots and the condensation agent through high-speed centrifugation; preparing a silica/quantum dot composite microsphere probe; and constructing an immunity-chromatograph test paper strip system. The invention has the advantages of simple and convenient detection method, accurate and visual results, high sensitivity, low price, and wide application and can be used for semi-quantitative detection and quantitative detection.

A vehicle stop determination apparatus includes a vehicle speed sensor for detecting a speed of a vehicle, a G sensor for detecting a longitudinal acceleration of a vehicle, an inclination acceleration estimate section for calculating an estimated inclination acceleration resulting from an inclination of a road surface based on a vehicle speed reduction rate calculated from an output of the vehicle speed sensor and an output from the G sensor, and a stop determination section which has a first stop determination mode and a second stop determination mode and which selects the first stop determination mode or the second stop determination mode based on the vehicle speed reduction rate provided before the output of the vehicle speed sensor becomes equal to or less than a detection limit. Also, the inclination is re-determined based on the output of the G sensor when the vehicle is stopped.

The present invention is directed to methods and compositions for assaying one or more analytes in a sample with improved sensitivity, reproducibility and/or lower detection limits, as well as applications employing such compositions and methods. In particular, the present invention provides methods and compositions for assaying one or more non-nucleic acid analytes with one or more other nucleic acid and/or non-nucleic acid analytes that serve as controls.

Improved apparatus is disclosed for carrying out axially illuminated laser induced fluorescence whole-column imaging detection in the capillary isoelectric focusing of proteins. The separation capillary was made of low refractive index Teflon conditioned with methylcellulose to reduce electroosmotic flow and a small amount of high refractive index organic solvent (glycerol) was added to the sample mixture. It was found that an axially directed laser excitation beam was propagated essentially with total internal reflection, so that minimum interference arose from stray light or from scattering light originating from the wall of the capillary. With the naturally fluorescent protein R-phycoerythrin, a concentration detection limit LOD 10⁻¹¹ M or mass LOD 10⁻¹⁷ Mo was obtained.

A single-mode optical fiber, cable, cord, and a method for ensuring a service life of the fiber are provided. The fiber has a core and a cladding, the fiber having a cut-off wavelength that exhibits a single-mode transmission in a 1.31 μm wavelength band. A relative refractive index difference of the core with respect to the cladding is adjusted such that a bending loss, when a bend is applied in a radius smaller than a limit bending radius of the fiber, becomes greater than a detection limit value. The limit bending radius is calculated from a relationship between a bending radius applied to the optical fiber and a failure probability which occurs after a time period. The method includes measuring a loss and ensuring that a failure probability of the fiber during a service life falls within a failure probability used for setting the limit bending radius.

Pork-specific PCR assay is performed for Halal authentication, by detecting porcine DNA in food products. DNA from raw meat samples is extracted. The extracted DNA is tested using primers that react by amplifying pork DNA but not beef and chicken DNA. The real-time PCR assay is sensitive with a low detection limit when using samples that can be obtained from food products. The methods described herein can have a sensitivity threshold as low as 0.001 ng pork DNA or lower, whereas convention techniques typically do not have a detection limit lower than 0.1 ng pork DNA.

The invention provides a substrate for surface enhanced Raman scattering. The substrate comprises a solid support, a zinc oxide nano rod layer, a noble metal nano particle layer and a hydrophobic layer, wherein the zinc oxide nano rod layer is formed on the surface of the solid support; the noble metal nano particle layer is formed on the zinc nano particle layer and covers the zinc nano particlelayer; the hydrophobic layer is formed on the surface of the noble metal nano particle layer; and the noble metal is gold or silver. Compared with the prior art, the substrate provided by the invention has good signal enhancing effect and high detection sensitivity, reduces the detection limit, and has good reproducibility. The invention also provides a preparation method for the substrate.

The present invention integrates the surface plasmon resonance and common-path phase-shift interferometry techniques to develop a microscope for measuring the two-dimensional spatial phase variation caused by biomolecular interactions on a sensing chip without the need for additional labeling. The common-path phase-shift interferometry technique has the advantage of long-term stability, even when subjected to external disturbances. Hence, the developed microscope meets the requirements of the real-time kinetic studies involved in biomolecular interaction analysis. The surface plasmon resonance microscope of the present invention using common-path phase-shift interferometry demonstrates a detection limit of 2×10⁻⁷ refractive index change, a long-term phase stability of 2.5×10⁻⁴π rms over four hours, and a spatial phase resolution of 10⁻³ π with a lateral resolution of 100 μm.

A flexible chemiresistor (CR) sensor for sensing a molecule of interest in a fluid (liquid or gas) is provided. The flexible CR sensor comprises a flexible chemiresistor (CR) module. The flexible CR module comprises a flexible substrate such polyethylene terephthalate (PET), polyethylene naphthalate (PEN) or polyimide (PI), and a thin film nanoparticle assembly assembled on the flexible substrate. The thin film nanoparticle assembly comprises metal or metal alloy core, ligand-capped nanoparticles and molecular linkers connecting the nanoparticles. The flexible CR sensor and an intelligent pattern recognition engine can be incorporated in a handheld device that can detect a molecule of interest in a fluid (e.g., a liquid or gas) accurately, rapidly, and without false positives. Any sensing array nanomaterial, pattern recognition, and compact/or electronic hardware can be integrated to achieve a desired detection limit and response speed.

The invention relates to a piece of surface enhanced raman detection test paper and the application thereof, which belong to the technical field of ultra-sensitive test analysis, in particular to the piece of surface enhanced raman detection test paper and the application of the paper to detection of biological or chemical probe molecules with raman signals. The surface enhanced raman detection test paper is obtained by covering a precious metal layer on the surface of paper with a natural fiber micro nano multi-grade structure through the physical vapor deposition or chemical plating technology, the paper can be filter paper, parchment paper, napkin, newspaper or printing paper and the like, the precious metal film is gold or silver and the like, and the thickness of the precious metal film is 5 nanometers to 90 nanometers. Combined action of size, period and roughness enables incident light to generate a local electric field on the surface of a multi-stage structure and enables the electric field to be enhanced, and the detection limit can reach 10-10mol/L. The test paper has the advantages of being good in flexibility, low in cost, free of environment pollution, capable of being prepared in batch and the like, thereby being capable of being used in detection of probe molecules such as rhodamine 6G, p-aminothiophenol, riboflavin or ethanol and the like.

The invention belongs to the technical field of laser probing, in particular to a laser probe micro-area component analyzer based on a double laser light source. The laser probe micro-area component analyzer comprises a fixed wavelength laser device, an attenuator, a beam expanding mirror and an aperture diaphragm; first semi-permeable half-mirrors are arranged on the same horizontal light path according to the structure; after a wavelength tunable laser device is reflected onto the first semi-permeable half-mirrors by a second totally reflecting mirror, the wavelength tunable laser device has the same light path with the laser beam of the fixed wavelength laser device; the fixed wavelength laser device and the wavelength tunable laser device can be arranged up and down or in parallel, and the starting sequence and the time delay thereof can be controlled by a digital delay generator; a fibre-optical probe receives laser, then the laser is transmitted to a grating spectrometer by the optical fibre, and the acquisition time of a plasma spectra reaching enhancement mode CCD is controlled by the digital delay generator. The laser probe machine stimulated by the double laser light sources has low detection limit, high element analysis precision and favourable element selectivity, is reliable and safe, and can be used for accurately determining the nature of microelements and trace elements of the micro-areas of various substances as well as carrying out accurate quantitative analysis.

A humidity sensor element, a humidity sensor device and a method for manufacturing thereof are provided. The humidity sensor element includes a substrate having a nanocomposite film as sensing material, wherein said nanocomposite film consists of carbon nanotube/perfluorinated polymer with acid functional groups in weight ratio of 0.01-20; and at least a pair of electrodes, which contact with the sensing material at one or both side(s). The nanocomposite film increases the sensitivity of humidity sensor element such that even an infinitesimal amount of moisture can be detected with minimum detection limit of 15.76 ppm_v

The invention discloses a chiral analysis method for nicotine in cigarette cut tobacco. The chiral analysis method for nicotine in cigarette cut tobacco is characterized by including the steps that cut tobacco samples are dried, smashed and screened, extracting liquid is added, the mixture is extracted and filtered, then common cut-tobacco-sample extracting liquid is directly analyzed through a multidimensional gas phase chromatography and mass spectrometry detector, cut-tobacco-sample extracting liquid with the excessively-low nicotine content is subjected to automatic solid phase microextraction to be subjected to multidimensional gas-phase-chromatography tandem-mass-spectrum analysis, and the proportion of S-(-)-nicotine and R-(+)-nicotine in the cigarette cut tobacco is quantitatively detected with the peak area normalization method. The detection method is simple, fast and convenient in sample treatment, low in method detection limit, high in sensitivity and good in accuracy degree, and analysis of cigarette cut tobacco samples can be met.

Improvements are provided in the detection of atmospheric vapors by ionizing them near ambient pressure, and analyzing them as ions. Lowest detection limits of parts per quadrillion (ppq) concentrations are enabled by a combination of improvements, including the use of a filter to remove occasional intense signal from explosive particles. Several sources of chemical background are identified and solutions for their reduction or elimination are presented. Gains in response time may be achieved by operating at elevated temperature. When the ionizer is an electrospray source, the use of high boiling point solvents is indicated. An increased selectivity is achieved by operating a differential mobility analyzer (DMA) in series with a mass spectrometer. However, ppq sensitivities require various improvements in the DMA system including a special coupling to the ionizer, controlling the temperature in the DMA pump circuit, avoidance of induction on the DMA electrodes from heating devices, etc.

The invention discloses a general rapid detection method for micromolecular poisonous and harmful substances in liquid milk. The method is characterized in that the method concretely comprises the following steps: 1, carrying out simple and general extraction and purification on a liquid milk sample to obtain a loading liquid; 2, preparing a mixed standard solution and a matrix addition standard curve; 3, determining the micromolecular poisonous and harmful substances in the liquid milk through UPLC-MS/MS; and 4, carrying out concentration calculation. The method of the invention has the following advantages: the method starts from general characteristics of micromolecular compounds and fully takes the dissolvability, the thermal stability, the acidic and basic stability, the polar strength, the coexistent stability and the like of all the substances into consideration, a general rapid preprocessing technology and a UPLC-MS/MS electro-spray apparatus determination technology are developed, and the substantial efficiency improvement and the detection cost reduction effect are brought to the production process control and food detection work on condition that detection limit requirements are satisfied.