45results about How to "Improve the lower limit of detection" patented technology

The invention discloses a method and a device for measuring sulfur content in coal by ultraviolet absorption spectroscopy. In the measurement method, the decomposition scale and a threshold are determined adaptively by combining empirical mode decomposition with 3sigma criterion, and non-stationary characteristics of differential absorption degree per se can be fully retained, so the spectral interference problem caused by dust, water vapor and background gas in combustion gas is effectively solved; the instantaneous concentration of SO2 is obtained through calculation according to the differential absorption degree after noise reduction and trend term removal, and the total sulfur content accumulated in the coal sample combustion gas is calculated through the gas flow; the sulfur content in the coal can be obtained by dividing the coal sample amount by the total sulfur content separated from the coal sample combustion; and the pretreatment process needed to be performed on the combustion gas by coulometric titration and an infrared absorption method is avoided. The device for measuring the sulfur content in the coal by the ultraviolet absorption spectroscopy comprises a combustion furnace, a measuring chamber, an ultraviolet light source, a spectrometer, an air purifying device, a flow meter, a waste gas treatment device, a computer, and the like.

The invention relates to a preparation method of a human IgG immunomagnetic bead (IMB) for staphylococcus aureus enrichment. With a magnetic bead as a carrier and human IgG as a recognition intermediate, the human IgG immunomagnetic bead is prepared through the processes of activation, coupling, washing and blocking. The human IgG immunomagnetic bead incubated in an appropriate buffer solution and under certain conditions can be used for high efficiency capture and enrichment of staphylococcus aureuses in a detection sample. The method of the invention has the advantages of strong specificity, high efficiency and rapidity, simple operation, low cost, and has no need for large equipment as well as specially trained professional operation personnel. Also, the sample needs no special pretreatment. Therefore, the method provided in the invention can be widely used for enrichment separation and detection of staphylococcus aureuses in food, feed, cosmetics, environment and clinics.

The invention relates to the technical field of molecular biology, and discloses a kit and a method for detecting COVID-19 virus by combining nested isothermal amplification with gene editing. The kitcomprises: (1) a nested isothermal amplification system: adopting a nested amplification mode, wherein an outer primer pair is used for a first round of isothermal amplification, an inner primer pairis used for a second round of isothermal amplification, a product of the first round of isothermal amplification can be used as a template of the second round of isothermal amplification, and the inner primer pair is used for isothermal amplification; (2) a nucleic acid detection system based on gene editing: using a Cas13a protease and a specific probe to identify a nested RAA enriched templatewith a target sequence; and (3) a visual detection system: utilizing a transverse flow test strip to quickly judge whether virus molecules exist or not. The kit is simple and convenient to operate, does not need complex temperature control equipment, is rapid and efficient, can interpret a result in only one hour, has extremely high amplification efficiency, can detect five copied virus molecules,and is low in pollution risk.

The invention provides a method for determining fluorine content in gypsum and silica. The method does not require ethanol to eliminate manganese, and uses alizarin S as an indicator, acetic acid-sodium acetate-sodium citrate-sodium chloride as a total ionic strength regulator. A fluoride ion selective electrode method is used to determine low levels of fluorine in gypsum and silica. The method can not only adjust the acidity and the ionic strength of the solution, but also mask the elements such as iron and aluminum in the solution. The method has high sensitivity, fast measurement speed, simple operation and small interference compared with other methods, and has good selectivity, which can provide accurate data.

The invention provides a mixed-potential low-ppm acetone sensor based on YSZ and a MNb2O6 (wherein M is one selected from a group consisting of Cd, Co, Zn, Mn and Ni) sensitive electrode and a preparation method. The mixed-potential low-ppm acetone sensor is mainly used for detection of diabetes. The sensor is successively composed of an Al2O3 ceramic plate with a Pt heating electrode, an YSZ substrate, a Pt reference electrode and the MNb2O6 sensitive electrode, wherein the reference electrode and the sensitive electrode are discrete and are symmetrically arranged on two ends of the upper surface of the YSZ substrate, the lower surface of the YSZ substrate is bonded with the Al2O3 ceramic plate equipped with the Pt heating electrode. According to the invention, the YSZ is used as an ionic conducting layer, and the MNb2O6 composite oxide material with high electrochemical catalytic activity is used as the sensitive electrode for construction of five sensing devices separately; and a device with higher sensitivity is obtained through comparison of acetone response values.

The invention discloses a sample preprocessing device provided with an ion chromatograph and used for detecting anions and a use method. The device comprises a sample liquid suck-in pipe, an absorption liquid storage bottle, a flushing liquid storage bottle, a sample liquid peristaltic pump, an absorption liquid peristaltic pump, a flushing liquid injection pump, a dialysis pool, an anion exchanger, a six-way valve, an absorption liquid storage ring and the ion chromatograph. The sample liquid peristaltic pump, the absorption liquid peristaltic pump, the ion chromatograph and the flushing liquid injection pump are all connected with a computer terminal. During dialysis, sample liquid flows, and absorption liquid stops flowing; when absorption liquid is transferred to the absorption liquid storage ring, sample liquid stops flowing, and absorption liquid flows; when the six-way valve is switched, the flushing liquid injection pump flushes absorption liquid in the storage ring to an anion enrichment column in the ion chromatograph. The device has the advantages of online removing heavy metal ions, being low in measurement limit, high in sample adaptability, mild in condition and free of toxic reagents, being matched with the ion chromatograph, and being capable of measuring various anions in sewage or acrylic fiber solvent within 20 min.

The invention relates to an immunomagnetic bead for aflatoxin B1 enrichment purification and a preparation method and application thereof. A carboxyl carboxyl serves as a carrier, an aflatoxin B1 monoclonal antibody serves as a recognition midbody, the immunomagnetic bead coupled with the aflatoxin B1 monoclonal antibody is prepared through the process of activating, coupling, washing and closing, and aflatoxin B1 in a detecting sample can be efficiently captured and enriched through incubation of the immunomagnetic bead in proper buffer liquid under certain conditions. The immunomagnetic bead for aflatoxin B1 enrichment purification has the advantages of increasing the concentration of aflatoxin B1 in the sample to be detected, improving the lower limit of detection, eliminating interference of impurities, improving detecting accuracy and reliability, shortening sample treatment time and achieving fast detection.

The invention discloses an online continuous gas sampling radioactivity measuring device which comprises a beta detector cathode, a beta detector anode and a gamma detector. The beta detector cathodeis of a hollow spherical shell structure, and the beta detector anode is a sphere; the beta detector anode is arranged in the beta detector cathode, and the sphere center of the beta detector anode coincides with the sphere center of the beta detector cathode; the beta detector cathode is insulated from the beta detector anode, and the gamma detector is arranged outside the beta detector cathode.The online continuous gas sampling radioactivity measuring device has the advantages that the online continuous gas sampling radioactivity measuring device capable of continuously sampling and simultaneously measuring beta and gamma is designed by the aid of the characteristic that beta and gamma rays can be simultaneously emitted by measured gas during nuclide decay, and has 4 pi detection stereoscopic angles for beta particles, beta and gamma measuring channels are matched with one another, accordingly, beta-gamma coincidence or anticoincidence measurement can be implemented, low radioactivity can be detected by the online continuous gas sampling radioactivity measuring device, and the lower limit of gas radioactivity detection can be improved during weak radioactivity measurement.

The invention relates to a graphene oxide aerogel solid-phase extraction column special for perfluoro acid compounds and a preparation method thereof. The solid-phase extraction column adopts grapheneoxide aerogel, and the preparation method comprises the following steps: firstly acquiring graphene oxide, then acquiring aminated graphene oxide hydrogel, then preparing aminated graphene oxide aerogel, and finally preparing the solid-phase extraction column. The graphene oxide aerogel prepared by the method does not need to use other polymer support materials, has excellent adsorption performance, can adsorb a lot of perfluoro acid compounds, has higher adsorption capacity and good adsorption effect, can quickly absorb target substances, and enables detection to be faster and more sensitive.

The invention relates to immunomagnetic beads for gathering purification of zearalenone and a preparing method and application of the immunomagnetic beads. The immunomagnetic beads coupled with zearalenone monoclonal antibodies are prepared through the process of activation, coupling, washing and enclosing with carboxyl magnetic beads as carriers and zearalenone monoclonal antibodies as recognition midbodies, the immunomagnetic beads are incubated in a proper buffer solution under a certain condition and can efficiently capture and gather zearalenone in a detection sample. The immunomagnetic beads for gathering purification of zearalenone have the advantages that the concentration of zearalenone in the detection is increased, the detecting lower limit is improved, interference of impurities is eliminated, the detection accuracy and reliability are improved, the sample treating time is shortened, and quick detection is achieved.

The present invention relates to an immunomagnetic bead used for vomitoxin enrichment purifying and a preparation method and application thereof, a carboxyl magnetic bead is used as a carrier, vomitoxin monoclonal antibody is used as an identifying intermediate, the immunomagnetic bead coupled with the vomitoxin monoclonal antibody is prepared by activation-coupling-washing-closed process, vomitoxin in a detection sample can be efficiently captured and enriched by incubation in certain conditions in a suitable buffer. The immunomagnetic bead used for vomitoxin enrichment purifying has the advantages of enrichment of concentration of vomitoxinin the to-be-tested sample, improvement of the lower detection limit, elimination of impurity interference, improvement of detection accuracy and reliability and reduction of sample processing time to achieve the rapid detection.

The invention discloses a biological sample detection method and a detection kit. The method comprises the following steps: forming a ternary complex (magnetic bead-antigen-marker) in a manner of immunospecific binding with magnetic beads, and collecting the ternary complex under the action of a magnetic field; under a specific chemical reagent, eluting a markers in the ternary immune complex, separating the markers from magnetic beads under the action of the magnetic field, and collecting eluent containing the markers, and re-dispersing the eluent by using strong electrolyte; and detecting the eluent containing the markers and then, realizing absolute quantification through a nano-particle counter. The method disclosed by the invention can be used for detecting trace protein below the lower limit of conventional immunodetection, and can be widely applied to the fields of immunological detection, microbiological detection, cell separation and the like.

The invention particularly relates to a method for rapidly determining the content of sulfite in industrial sulfuric acid, which belongs to the technical field of chemical analysis and detection, andcomprises the following steps: taking an industrial sulfuric acid sample with the mass of m, and performing preparing to obtain a solution to be detected; titrating the to-be-detected solution by adopting a closed titration device to obtain the volume V of a standard titration solution consumed at a titration end point; setting a blank test group, and obtaining the volume V0 of the standard titration solution consumed at the titration end point; obtaining the content of sulfite in the industrial sulfuric acid according to m, V and V0; the closed titration device comprises a conical flask, a rubber plug, a glass gas-guide tube, a burette and a magnetic stirrer, wherein the rubber plug is tightly plugged at the opening of the conical flask; the glass gas-guide tube and the burette respectively penetrate through the rubber plug, so that one end of the glass gas-guide tube and one end of the burette extend into the conical flask and are respectively used for introducing nitrogen, discharging oxygen and titrating a solution of the conical flask; and the magnetic stirrer is positioned at the bottom of the conical flask and is used for stirring the solution in the conical flask.

The invention discloses a liquid chromatogram-inductively coupled plasma mass spectrometry detection method of vitamin B12. According to the liquid chromatogram-inductively coupled plasma mass spectrometry detection method of vitamin B12, high performance liquid chromatography and inductively coupled plasma mass spectrometry are combined, so that the obtained liquid chromatogram-inductively coupled plasma mass spectrometry detection method of vitamin B12 is stable and reliable, is high in anti-matrix interference performance, low in detection limit, simple in operation, and high in speed, and is especially suitable for determination of vitamin 12 in food, and novel reference is provided for detection and analysis of vitamin B12 in food.

The invention discloses a conical space compression plasma detection system, a space compression technology is applied in plasma detection, and the ability of plasma detection of various elements and the detection lower limit are enhanced. The conical space compression plasma detection system is a system which can independently complete element detection and material component content detection; the system is mainly composed of a light source module, a conical compression module, a sample module, a detection module, a logic module and a display module; the logic control module is connected with the control module, the detection module and the display module; the control module achieves manipulation of the light source module and the detection module; the light source module completes work of light on the sample module through the conical compression module; the detection module is used for collecting information of the sample module and transmitting to the logic module. The plasma detection system has better detection precision and lower detection lower limit than those of a traditional system, and can realize zero pretreatment of samples.

The invention discloses an electromagnetic acceleration enhanced plasma detection system which combines electromagnetic acceleration with a laser plasma excitation detection technique. The electromagnetic acceleration enhanced plasma detection system provided by the invention is a system capable of completing material element and component content detection. The detection system mainly comprises a light source module, an electromagnetic acceleration module, a sample module, a control module, a probing module, a logic module and a display module; the logic module is connected with the control module, the probing module and the display module; the control module realizes the control on the light source module, the electromagnetic acceleration module and the probing module; light emitted from the light source module irradiates a to-be-detected object on the sample module and induces plasma, the plasma enters the probing module under the action of the electromagnetic acceleration module, and the detection collects sample module information and transfers the sample module information to the logic module. The electromagnetic acceleration enhanced plasma detection system provided by the invention has better probing precision and lower detection limit, and realizes zero pretreatment on a to-be-detected sample.