145results about How to "Quantitatively accurate" patented technology

The invention discloses a phased array ultrasonic detection method for anisotropic metal plate weld joints. The phased array ultrasonic detection method comprises the following steps: S1, preparation work before detection; s2, selecting instruments and detection parameters; s3, adjusting the detection system; s4, detection is carried out, wherein base metal detection is carried out on the peripheral area of the metal plate weld joint, and it is ensured that no defect affecting acoustic beam propagation exists in the base metal of the metal plate; s2, according to the instruments and the detection parameters selected in the step S2, scanning all the areas of the weld joint in sequence, and storing scanning detection data; and S5, detection result analysis: analyzing the stored scanning detection data, finding out defect signals, recording corresponding defect information, and correcting the defect information to obtain final accurate information corresponding to the defect signals. According to the method, a large number of calibration test blocks do not need to be manufactured, and the final accurate information corresponding to the defect signal can be obtained only by correcting the found defect information, so that the workload is reduced, and the detection efficiency is improved.

The invention discloses a method for detecting the hydrazine content in a medicine containing carbidopa. The invention provides a method for detecting hydrazine content in a medicine containing carbidopa, which comprises the following steps: (1) mixing a sample to be detected and an aldehyde substance in a solvent under the action of acid, deriving hydrazine in the sample to be detected and the aldehyde substance to obtain a test solution, and (2) detecting the content of hydrazine in the test solution. Compared with the prior art, the method has the advantages that the carbidopa does not need to be removed through pretreatment, hydrazine introduced in the determination process can be ignored, operation is simple, derivatization time and sample injection time do not need to be accurately controlled, repeatability is good, and quantification is accurate.

The invention discloses a three-dimensional laser post-ionization-secondary neutron particle mass spectrometer which comprises a vacuum pool, a sample introduction system, a primary ion emission system, a three-dimensional laser post-ionization system, an ion optical system, a time-of-flight mass spectrometer, an observation system and a computer control system. By adjusting the wavelength, the frequency and the energy value of the laser, resonance between the energy of laser photons and the electron energy level of target molecules can be realized to realize selective ionization of substances, and the method has extremely high element, nuclide and molecule selectivity, can provide the sensitivity of an instrument, and can be used for mass spectrometry. The device can be applied to single-cell imaging analysis test of lipid, metabolites, small-molecule drugs and part of elements with the molecular weight smaller than 1000 Da, the problems of space metabolome small-molecule metabolite test and ultrahigh spatial resolution imaging are solved, and the device can be independently used as an SIMS when laser post-ionization is not used.

The invention discloses a high-precision electromagnetic plunger metering pump which comprises a pump body, a valve body, an electromagnetic control device and a plunger assembly. The electromagnetic control device comprises a movable iron core which is movably arranged and an electromagnet assembly for controlling the movable iron core to move; the plunger assembly comprises a positioning ring, a buffering heat insulation ring and a plunger rod, the positioning ring is provided with a containing groove and a via hole, a first rotation limiting structure is arranged between the positioning ring and the pump body, the buffering heat insulation ring is arranged in the containing groove and connected to the movable iron core, and a second rotation limiting structure is arranged between the buffering heat insulation ring and the positioning ring. The plunger rod penetrates through the via hole and extends into the plunger moving groove, and a sealing assembly is arranged between the periphery of the plunger rod and the plunger moving groove. The arrangement of the buffer heat insulation ring can prevent the heat of the movable iron core from being transmitted to the plunger rod, limit the rotation of the positioning ring relative to the pump main body and limit the rotation of the buffer heat insulation ring relative to the positioning ring, so that the plunger rod can be ensured to hit the same position of the plunger moving groove every time, and the quantification is more accurate.

The invention relates to the field of molecular biology and clinical medicine, and relates to a double-split aptamer probe and application thereof. The double-split aptamer probe comprises two split aptamers, namely a split aptamer 1 and a split aptamer 2, the split aptamer 1 comprises an aptamer fragment 1 and a split initiator 1, the split aptamer 2 comprises an aptamer fragment 2 and a split initiator 2, and the two aptamer fragments are from a complete aptamer sequence A. The invention further discloses a preparation method of the double-split aptamer probe. The invention proves that DNA (deoxyribonucleic acid) can be successfully self-assembled in a solution to form a fluorescence tree with larger molecular weight under the triggering of a target, so that signal amplification is realized. The constructed sandwich-type fluorescence sensor can be successfully applied to Ade detection, in the concentration range of 0.01-100 ng / mL, the detected fluorescence intensity is enhanced along with increase of the concentration of Ade, LOD is not higher than 5.23 pg / mL, the detection time is not longer than 30 min, and the sandwich-type fluorescence sensor has the advantages of being high in sensitivity and short in detection time.

The invention relates to a dispensing machine, in particular to a dispensing machine for packaging a glue cap, a dispensing method and a cleaning method, and overcomes the defects that the dispensing effect cannot be accurately controlled and the requirements of products with high dispensing requirement precision cannot be met due to the fact that the glue amount and the dispensing position precision of existing contact type dispensing are not high. The dispensing machine comprises a glue spraying valve, a displacement unit, a power unit and a control unit, the displacement unit is used for controlling the glue spraying valve to move, and the glue spraying valve comprises a valve body, a firing pin assembly, a nozzle, a runner assembly and a heating base. The striker assembly comprises a striker, a compression spring and a piezoelectric module, the bottom end of the striker corresponds to the nozzle, the top end of the striker is connected with the piezoelectric module, and the piezoelectric module is used for controlling the striker to act. The heating module is used for heating glue, the glue enters the nozzle through the flow channel assembly, the piezoelectric module drives the firing pin to move up and down to achieve glue spraying, the invention further provides a glue dispensing method and a cleaning method based on the glue dispenser, and efficient work is achieved.

The invention discloses a method for determining the contents of ester solvents and additives in a sodium-ion battery electrolyte by GC-MS. Through preparation of a diluent, selection of a program method and control of conditions, the types and contents of the solvents and the additives in the sodium-ion battery electrolyte can be rapidly and accurately determined in one step. Therefore, the method can be widely applied to the field of component analysis of the sodium-ion battery electrolyte.

The invention discloses an enhanced anti-fluorescence quenching mounting medium as well as a preparation method and a mounting method thereof, particularly relates to the technical field of immunofluorescence, and aims to solve the problems that a fluorescent dye is rapidly attenuated under the irradiation of strong exciting light and the like in the prior art. Every 100 mL of the mounting medium comprises 15-30 mL of an acid-base buffer solution, 10-20 mL of a viscosity modifier, 0.5-5 g of a fluorescence quenching resistant compound, 1-15 mL of a synergist and the balance of distilled water, and the fluorescence quenching resistant compound comprises triethylene diamine and ethylenediaminetetraacetic acid. The mounting medium provided by the invention can enhance the overall fluorescence brightness and maintain the stability of fluorescence under excitation light, thereby realizing more accurate quantification of fluorescence signals.

The application belongs to the technical field of detection, and particularly relates to a method for determining the content of chlorhexidine acetate in a disinfectant. The method for determining the content of chlorhexidine acetate in the disinfectant comprises the following steps: (1) dispersing the sample with glacial acetic acid, releasing chlorhexidine acetate combined with sample matrix components, and extracting with a methanol aqueous solution; and (2) taking a tetrabutylammonium bromide-acetic acid-acetonitrile solution as a mobile phase, and detecting with a high-performance liquid chromatograph. The method for detecting chlorhexidine acetate is simple in operation, good in reproducibility, complete in separation from impurities, high in accuracy, and has a good application prospect.

The invention relates to a synchronous detection method for impurities contained in candesartan cilexetil and amlodipine besylate, which is suitable for quality control of compound preparations. According to the method, a high performance liquid chromatography technology is adopted, an octadecyl silane bonded silica gel column is used as a chromatographic column, gradient elution conditions are optimized, a water-acetonitrile-trifluoroacetic acid mixed solution is used as a mobile phase A, and an acetonitrile-water-trifluoroacetic acid mixed solution is used as a mobile phase B; according to the method, the impurity contents of amlodipine besylate and candesartan cilexetil are respectively detected under the wavelengths of 240 nm and 253 nm through gradient elution, the separation degree R value is greater than 1.5, the detection sensitivity is high, and the lower quantification limit reaches 0.05%. The method can simultaneously separate and quantify various process impurities and degradation impurities of candesartan cilexetil and amlodipine besylate in the compound preparation, and has the characteristics of high efficiency, accuracy and stability. The method is easy and convenient to operate, low in cost and suitable for compound preparation quality control under the industrial production condition, and scientific support can be provided for improving the medicine quality standard.

The invention discloses a time-space resolution single cell transcriptome detection method, which comprises the following steps: firstly, carrying out specific marking on RNA newly generated by cells within a specific time by using a metabolism marking technology so as to ensure that new RNA molecules can be accurately identified and tracked; then, signal amplification of a new RNA target is realized through an adjacent rolling circle amplification (PLA-RCA) technology, and the detection sensitivity is improved; and finally, realizing high-throughput analysis on the newborn RNA by using an in-situ fluorescence sequencing technology, and carrying out accurate space positioning and quantification on the newborn RNA in the single cell by the step. Through the method, time and space resolution analysis can be provided for a single cell transcriptome, so that analysis of complex biological processes such as cell differentiation, disease occurrence and cell function response is facilitated; moreover, the method has important significance for revealing a molecular mechanism in a cell biological process, and provides a new visual angle and tool for disease diagnosis and treatment.

The invention discloses a label printer core, and relates to the technical field of printer cores. The device comprises a base body and an upper cover body rotationally connected to the upper end of the base body, and further comprises a connecting rotating shaft arranged at the upper end of the base body; the thermal transfer ribbon conveying assembly is arranged in the upper cover body; the driving motor is fixed in the base body, and one side in the base body is transversely and rotationally connected with a paper pressing roller; the linkage mechanism is arranged at the output end of the driving motor; the paper thickness quantitative adjusting mechanism is arranged on the inner side of the upper cover body. Through the linkage rod, the upper cover body can be locked and limited through the first buckle teeth and the second buckle teeth, the current-conducting plate is arranged at one end of the linkage rod and is grounded, the thermal transfer ribbon is attached to the outer side of the linkage rod, static electricity on the thermal transfer ribbon is guided out through the current-conducting plate by the linkage rod, and the static electricity on the thermal transfer ribbon is discharged through the current-conducting plate. The printing quality of the printing head can be improved, the service life of the printer can be prolonged, the arranged PCB body can be detached and replaced, and the PCB body can be used independently and can also be used separately.

The invention relates to the technical field of chemical analysis, in particular to a method for detecting free carotenoid in chili. The detection method comprises the following steps: detecting the capsicum extract by using ultra-high performance liquid chromatography-tandem mass spectrometry, and the liquid chromatography in the ultra-high performance liquid chromatography-tandem mass spectrometry comprises the following mobile phase components: a mobile phase A: methanol or acetonitrile, formic acid and ammonium formate, the volume percentage of formic acid in the mobile phase A is 0.05-0.2%, the volume percentage of ammonium formate in the mobile phase A is 0.05-0.2%, and the volume percentage of ammonium formate in the mobile phase A is 0.05-0.2%; the concentration of ammonium formate in the mobile phase A is 4.5-5.5 mM; and the mobile phase B is an MTBE (Methyl Tert-Butyl Ether) solution containing 0.005 to 0.02 g / 100mL of antioxidant. The detection method can accurately detect the free carotenoid in the pepper and perform quantitative analysis, and meanwhile, the detection method is simple and rapid to operate, high in sensitivity and good in repeatability.

The invention discloses an analytical method for detecting related substances in umeclidinium bromide and vilanterol compound preparations, using high performance liquid chromatography, a phenyl column whose filler is phenyl-hexyl chemically bonded silica gel is used as a chromatographic column, and a mobile phase adopts a sodium perchlorate solution and an acetonitrile system, and a sodium perchlorate solution concentration is 0.1-0.3 mol / L, with a sodium perchlorate solution as a mobile phase A, and acetonitrile as a mobile phase B, using gradient elution. The present invention makes up for the drawbacks of the lack of umeclidinium bromide and vilanterol compound preparation related substance inspection methods in the prior art, using a commonly used detector, by a single injection can simultaneously realize the inspection of the impurities introduced by two active ingredients, the method has low detection cost and high efficiency; strong specificity, good separation between each impurity peak and between the active ingredient and the impurity peak, and no mutual influence; the detection limit and quantitative limit of impurities are reasonable, and the sensitivity is high; accurate detection and quantification of impurities can be achieved.

The invention provides an intestinal ruminococcus albus nucleic acid quantitative detection method and application. Relates to the technical field of nucleic acid detection. The primer group comprises a primer pair and a probe, wherein the primer pair and the probe have specificity with a ruminococcus albus cel48A gene; the primer pair comprises a forward primer and a reverse primer; the nucleotide sequence of the forward primer is as shown in SEQ ID NO. 1; the nucleotide sequence of the reverse primer is as shown in SEQ ID NO. 2; and the nucleotide sequence of the probe is as shown in SEQ ID NO.3. The primer group provided by the invention has high specificity and sensitivity aiming at the ruminococcus albus cel48A gene, and can accurately detect and quantify target microorganisms. The operation process is simplified, the non-specific reaction risk is reduced, the method is suitable for various sample types, and the application range is widened. In addition, cost is reduced, data reliability is improved, a new tool is provided for disease monitoring, and technical innovation is promoted.

The utility model discloses a quantitative strain packaging connector which comprises a stocker used for storing quantitative strains; the water storage device is used for storing quantitative clear water; the connector is used for connecting the material storage device and the water storage device; a connecting cavity is formed in the connector, the water storage device is located above the material storage device, and after the water storage device moves relative to the connector, the water storage device is communicated with the connecting cavity, so that clear water in the water storage device flows into the material storage device; the device has the advantages of being compact in structure, accurate in quantification, convenient to operate and excellent in sealing performance.

This invention discloses a wide dynamic range substrate reagent, belonging to the field of biological detection reagent technology. The reagent consists of the following components: citric acid, 9.6 g / L; 3,3',5,5'-tetramethylbenzidine, 0.29 g / L; 3% hydrogen peroxide solution, 3 mL / L; 1 g / L polyvinyl alcohol; 0.5 g / L copovidone W-735; 0.5 g / L dimethyldiallylammonium chloride-acrylamide copolymer; 1 g / L PVP K30; and Tween 20, 0.005 g / L. mL / L; polyethylene glycol 10g-50g / L; pure water, balance. This invention, by adding specific polyethylene glycol and synergistically combining with other components, significantly reduces the reagent background signal and improves detection sensitivity; effectively broadens the detection dynamic range and increases the detection upper limit of high-concentration analytes; improves the linear correlation between signal and concentration; and enhances the thermally accelerated stability of the reagent. This reagent has comprehensive performance and is especially suitable for ELISA detection systems with high sensitivity and wide detection range.

The invention belongs to the technical field of cosmetic production, and particularly relates to a cosmetic production conveying system and a conveying process thereof.The cosmetic production conveying system comprises a workbench, an annular fence is fixedly installed at the top of the workbench, a feeding port and a discharging port are formed in the outer wall of the annular fence, and a transmission belt is fixedly arranged at the top of the workbench; the transmission belt is matched with the feeding hole of the annular fence; through cooperation of a lifting plate and a lifting sleeve, the distance between conveying discs can be flexibly adjusted, the cosmetic bottle filling device is suitable for cosmetic bottles of different heights, and through a filling assembly composed of a flexible rubber hose, a fixed plate, a base plate, a movable plate, an extrusion hammer and the like in combination with the groove design of a first driving disc, accurate control and quantitative filling of cosmetic solutions are achieved.

The invention provides a high-flux monosaccharide separation and quantification method and kit based on gel electrophoresis. The separation and quantification method comprises the following steps: (1) providing a fluorescence-labeled monosaccharide sample to be detected; (2) injecting the monosaccharide sample to be detected into a capillary electrophoresis system, and performing first electrophoretic separation under a first separation system to obtain a first electrophoretogram; the first separation system comprises borate-free first separation gel and a first buffer solution; (3) cleaning a capillary tube of the capillary electrophoresis system, injecting the monosaccharide sample to be detected into the capillary tube again, and performing electrophoretic separation for the second time in a second separation system to obtain a second electrophoretogram; the second separation system comprises second separation gel containing borate and a second buffer solution; and (4) carrying out qualitative identification and quantitative calculation on the mixed monosaccharide according to the migration time difference and peak overlapping condition of each monosaccharide component in the first electrophoretogram and the second electrophoretogram.

The invention discloses a headspace-gas chromatography detection method for 1, 3-butadiene in an automotive interior material, which comprises the following steps: 1) crushing a sample into fine particles, freezing with liquid nitrogen, embrittling, and crushing at low temperature; and (2) weighing a sample which is recovered to room temperature after being crushed, putting the sample into a headspace bottle, quickly sealing, and carrying out gas chromatography detection in a headspace sampling mode. On the basis of the headspace-gas chromatography technology, by optimizing headspace sampling conditions, instrument parameters and chromatographic column selection, the 1, 3-butadiene detection method which is simple and convenient in pretreatment, high in sensitivity and accurate in quantification is established. And the method is precisely positioned on a specific and complex substrate, namely an automotive interior material. Compared with the prior art, the method is simple and convenient to operate and high in detection speed, can effectively avoid the problems of incomplete dissolution, difficulty in sample introduction and the like, is suitable for measuring an actual sample, and provides a reliable technical means for detecting the residual quantity of 1, 3-butadiene in the automotive interior material.

The utility model discloses a liquid food pipettor which comprises a pipetting frame, a square hole is formed in the pipetting frame, an electric sliding rail is fixedly connected in the square hole, the electric sliding rail is in power connection with a sliding block, the upper end face of the sliding block is fixedly connected with a pipetting storage tank, and the upper end face of the sliding block is fixedly connected with two electric push rods which are in bilateral symmetry. The electric push rod penetrates through the sliding block to be in power connection with the upper end face of the connecting plate, a telescopic rod of the electric push rod is connected with the sliding block in an up-down sliding mode, a pipetting storage cavity is formed in the pipetting storage tank, the pipetting storage tank is fixedly connected with a breathable film, the breathable film plays a role in ventilation and dust prevention, and the lower end face of the connecting plate is fixedly connected with a pipetting suction pipe. A liquid pump is fixedly connected to the upper end face of the connecting plate, an electromagnetic valve is fixedly connected into the sliding block, a conveying hose is fixedly connected between the electromagnetic valve and the liquid pump, the electromagnetic valve can communicate with the conveying hose and the pipetting storage cavity, and the liquid pump can communicate with the pipetting suction pipe and the conveying hose.

This invention provides a method for detecting tetrachloronaphthalene, a persistent organic pollutant in eel products. The specific steps include: eel sample preparation, target analyte extraction and matrix purification, followed by analysis using ultra-high performance liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry (UPLC-APCI-MS / MS). The measured peak area, fractionation ratio, and other relevant parameters are substituted into a specific formula to calculate the measured value of tetrachloronaphthalene in the test solution. This method fills the gap in my country's technology for detecting tetrachloronaphthalene-like persistent organic pollutants in eel products. It effectively eliminates interference from the complex matrix of eel products, accurately determines four tetrachloronaphthalene isomers in trace amounts, and possesses significant advantages such as high sensitivity, strong anti-interference ability, simple operation, and high detection accuracy.

The invention discloses a Mycobacterium tuberculosis double-target joint detection kit and a detection method, IS6110 and mpt64 genes are screened and determined as target genes for double-target joint detection of Mycobacterium tuberculosis, the detection false negative rate is reduced to a great extent, and the detection precision is improved. According to the invention, two pairs of specific primers and two probes are designed and synthesized, efficient, rapid and accurate double-target joint detection of mycobacterium tuberculosis is realized, the sensitivity and the specificity both reach 95% or more, and the matching degree of the two probes for joint detection of mycobacterium tuberculosis exceeds 90%. A unique reaction system is designed to carry out real-time fluorescent quantitative PCR, primer probes do not interfere with one another, amplification detection can be carried out at the same time, and high sensitivity and specificity are achieved. The sample does not need to be cultured, and the mycobacterium tuberculosis can be rapidly and accurately detected through sputum, so that the quantitative and qualitative detection of the mycobacterium tuberculosis is realized.

The utility model belongs to the technical field of quantitative conveying equipment, and discloses quantitative conveying equipment for rice packaging, which comprises a rack and a plurality of supporting legs fixed at the bottom of the rack, a storage tank is arranged at the top of the rack, a discharge tank is arranged in the rack and below the storage tank, and a plurality of conveying belts are arranged in the discharge tank. A flow guide frame is fixedly mounted at the bottom of the rack, a quantitative barrel is rotationally mounted in the rack and located between the storage tank and the flow guide frame, a quantitative adjusting mechanism is arranged in the quantitative barrel, and a quantitative cavity is formed by one side of the quantitative adjusting mechanism and the inner wall of the quantitative barrel; and the quantifying cavity can be sequentially communicated with the discharging groove and the flow guide frame through rotation of the quantifying barrel. The quantitative conveying device is provided with the quantitative barrel, the quantitative conveying process of rice is quantified by adopting a quantitative cavity constant volume mode, the falling impact force of the rice cannot be influenced, and the rice in the air does not exist, so that the quantitative mode is more accurate.

The invention provides a multi-sensing module combined hydrogen detection method and system under a room temperature condition, and relates to the technical field of hydrogen sensors, and the method comprises the following steps: obtaining output signals of a first sensing module and a second sensing module in real time; when the signal value output by the first sensing module is higher than a preset safety value, a first alarm is given; when the response rate of the output signal of the first sensing module is higher than the preset response rate value, sealing of the second sensing module is relieved, and a second alarm is given out according to the output signal value of the second sensing module. According to the invention, seamless and graded monitoring of hydrogen from low concentration to ultrahigh concentration can be realized, room temperature stable induction during low-concentration hydrogen leakage can be ensured, and accurate quantification can be carried out during high-concentration hydrogen leakage; the high-value sensing module is always in a sealed state to effectively protect the value, the low-value sensing module adopts indium doped molybdenum oxide nanobelts to ensure long-time stable use at room temperature, and the two sensing modules are combined and complemented, so that the hydrogen detection safety is higher.

The present invention discloses a water system extraction method based on a digital elevation model (DEM). The field of water system extraction methods related to digital elevation models belongs to the field of geoscience. The water system extraction method based on a digital elevation model (DEM) comprises the following steps: step (1): pre-processing the data to be operated, logging into a geospatial data cloud network platform to cut and download the selected area data, mosaicking the obtained area data, and adding administrative district boundaries as references; step (2): using ArcGIS's own system toolbar to fill the original DEM data, extracting the flow direction of the filled depression, using the flow direction as input, outputting flow data, and calculating the flow direction accumulation grid. Based on the digital elevation model (DEM), the present invention realizes the extraction of rivers, water outlets and watersheds by simulating the process of surface water forming runoff, which is convenient and fast, and the extraction of small watersheds is more accurate and clear.

The application belongs to the technical field of chemical analysis, and particularly relates to a detection method for D-glycophosphocholine content in L-alpha-glycophosphocholine and application. The detection method selects a silica gel surface polysaccharide covalent bonding cellulose type or silica gel surface polysaccharide coating cellulose type normal phase chromatographic column and an evaporative light scattering detector (ELSD), detects through an HPLC-ELSD method, has the advantages of simple operation, high sensitivity, good method specificity and reproducibility, is a high-efficiency liquid phase analysis method convenient for standardized operation, can completely separate L-alpha-glycophosphocholine from low-limit D-glycophosphocholine isomer impurities, and can accurately quantify.

The utility model discloses a portable medicine dispensing device which comprises a needle tube, a push rod is inserted into one end of the needle tube in a sliding mode, blocking pieces are arranged on the two sides of the end, a clamping portion is arranged at the outer end of the push rod, the portable medicine dispensing device further comprises an installation cylinder, a fixing mechanism and an extraction mechanism, the fixing mechanism comprises an installation assembly and a locking assembly, and the installation assembly is arranged at the open end of the installation cylinder; the locking assembly is used for clamping the needle tube and enabling a push rod of the needle tube to be located in the mounting cylinder, and the needle tube and the mounting assembly can be fixed through the locking assembly; the extraction mechanism comprises a driving assembly and a limiting assembly, the driving assembly can drive the push rod to be close to or away from the needle tube, the limiting assembly is used for limiting the maximum moving distance of the push rod away from the needle tube, and when medicine dispensing is needed, the needle tube is clamped to the fixing mechanism, and at the moment, the needle tube is automatically positioned and locked through the fixing mechanism; the limiting assembly is adjusted to the needed position, the driving assembly is started at the moment, the driving assembly drives the needle tube to extract the medicine, the driving assembly is limited through the limiting assembly, and therefore quantitative medicine extraction is achieved.

The invention discloses an LC-MS (liquid chromatography-mass spectrometry) detection method of alpha-hydroxybutyric acid, and belongs to the technical field of quantitative detection of alpha-hydroxybutyric acid. The detection method comprises the following steps: step 1, preparing a standard working solution; 2, preparing an internal standard working solution; step 3, pre-treating a sample; step 4, putting the sample treated in the step 3 into EP tubes, adding an internal standard working solution into each EP tube, slightly and uniformly mixing, continuously carrying out vortex oscillation on the mixture at the room temperature at the medium speed, then carrying out centrifugal treatment, and transferring supernatant liquid in a centrifugal tube into a special bottle for liquid chromatography; and 5, placing the special bottle for liquid chromatography on a sample introduction disc of a high performance liquid chromatography-tandem triple quadrupole mass spectrometer, carrying out data acquisition and quantitative analysis, recording a chromatogram and a mass spectrum, and carrying out peak area calculation by adopting an internal standard method to obtain a detection result. The 2-HB can be accurately detected and quantified, and the metabolic state of a patient can be more accurately evaluated.

The utility model provides a quantitative feeding device for a vacuum die-casting machine and a feeding method of the quantitative feeding device, and belongs to the technical field of feeding devices. The feeding device comprises a vacuum exhaust system, a mold cavity, a melting cup, an alloy melt holding furnace and a punch. According to the feeding method, the principle of dynamic pressure difference and dynamic height difference is utilized, the quantitative weight is set, and precise aluminum alloy die-casting quantitative feeding is achieved in the mode that the pressure difference between the atmosphere and a mold cavity and / or melting cup vacuum and the liquid level height difference between the melting cup and an alloy melt heat preservation furnace are balanced. According to the utility model, the melting cup is communicated with the alloy solution holding furnace through the riser tube, the alloy solution in the melting cup is injected into the mold cavity through the punch, and the liquid suction process is the exhaust process, so that the filling rate can be improved or completely canceled, the quantitative feeding and vacuum exhaust efficiency is greatly improved, the feeding and injection time is shortened, and the production efficiency is improved. The defects caused by temperature drop of conventional alloy feeding are avoided, the production efficiency is improved, and the equipment cost is greatly reduced.