146results about How to "Analytical method is accurate" patented technology

The invention relates to a preparation method of liquid calcium chloride, in particular to a method for producing the liquid calcium chloride by using the waste industrial acid, which belongs to the technology field of chemical industry. The preparation method is characterized in allowing massive limestone and waste hydrochloric acid obtained by acid washing strip steel to react at a certain ratio and neutralizing with lime cream to obtain calcium chloride at a certain concentration. Proved by the production, the preparation method is capable of effectively reducing the production cost and achieving comprehensive utilization of the waste industrial acid and remarkable economic and social benefits.

The invention discloses a hemolytic agent for a blood cell analyzing device. The hemolytic agent can decompose erythrocytes and blood platelets in blood. The invention also discloses a leukocyte classification kit. The leukocyte classification kit comprises the hemolytic agent, a dilute and an inhibitor. The agent provided by the invention is the assorted agent suitable for XFA9500 fully-automatic five-classification blood cell analyzer produced by Nanjing Perlong medical equipment limited company; the agent contains no dye, so that the agent is environment-friendly; by adopting the agent, lymphocyte, monocyte, neutrophile granulocyte, eosinophilic granulocyte and basophilic granulocyte can be directly detected; furthermore, the analysis method is fast and accurate.

The invention belongs to the technical field of food detection, and particularly relates to a fast instrumental analysis method for aflatoxins in foods. The invention discloses a fast instrumental analysis method for aflatoxins B1, B2, G1 and G2 in foods. The method comprises the following steps of: weighing a certain amount of sample; adding an acetonitrile-water solution in a certain ratio; performing ultrasonic extraction; and selecting specific parent ions and daughter ions by using a super-efficient liquid phase chromatography-mass spectrometer under a gradient elution condition to measure the content of the four types of aflatoxins. The method is simple and is high in efficiency and the precision of measurement results is high. By the method, four monomers of the aflatoxins are completely separated, and the recovery rate is high; and compared with the prior art, the method has the advantages of high speed and accuracy of detection and simple pretreatment, and can be used for accurately determining the nature and the quantity to meet requirements on research and detection.

The invention discloses a method for detecting content of short-chain or medium-chain chlorinated paraffin in a paint. The method comprises the following steps: extracting the short-chain or medium-chain chlorinated paraffin in the paint, detecting with a gas chromatography-negative chemical ionization source mass spectrometry detector, using the internal standard method, performing linear association on a total response factor of a short-chain or medium-chain chlorinated paraffin standard sample on the NCI (negative chemical ionization) mass spectrometry detector with the chlorine content of a short-chain or medium-chain chlorinated paraffin standard solution, detecting the actually measured chlorine content of the sample by the gas chromatography-negative chemical ionization source mass spectrometry detector, corresponding the actually measured chlorine content with the a liner reaction expression of the total response factor and the chlorine content of the short-chain or medium-chain, to obtain the total response factor of the sample, and thus obtaining the content of the short-chain or medium-chain chlorinated paraffin in the paint. The analysis method disclosed by the invention is exact and fast, has small interfering, and can perform optimal separation and qualitative and quantitative detections on each component in the sample.

The invention discloses a method for rapid detection of the residual mount of sulfanilamide in food. The method comprises the following steps: firstly enabling the sulfanilamide and fluorescamine to perform derivation reaction, further enriching derivative products by using cloud point extraction, adding a sample enrichment and a standard plate prepared from a sulfanilamide standard product on a thin layer silica gel plate, comparing the fluorescence intensities of the two under an ultraviolet lamp to judge the concentration range of the fluorescamine in a sample, and determining the residual amount of the sulfanilamide in the food, wherein a detection limit of the method is 0.08 micron g / mL. The method disclosed by the invention has the advantages of simplicity in operation, small using amount of organic solvent, high detection sensitivity, short detection time, strong specificity and capability of realizing effective separation from interfering substances, is a simple, convenient, fast and accurate analytical method, does not need large-scale instruments, only needs to configure small-scale instruments and equipment, and further has extensive application prospects.

The invention provides a method for testing the alkyl quaternary ammonium salt cationic, which includes the following steps: processing a pretreatment for the test sample; testing with a gas-chromatography-mass spectrometer, setting the injection port temperature of the instrument at 180-350 EDG C, setting the carrier gas flow rate at 0.5-2.0 ml per minute, the chromatographic column is a nonpolar, weak polar or strong polar column, setting the port temperature at 180-300 EDG C; injecting the pretreatmented sample into the chromatographic column through the injection port of the instrument, processing the programmed temperature, from 40-120 EDG C up to 210-320 EDG C, processing the mass spectrometric detection after each component of the decomposition products of the sample is separated by the chromatographic column. The method provided by the invention has the merits of cheap test instrument, safety, accurate and fast analysis method and small disturbance, which causes the alkyl quaternary ammonium salt cationic in the sample to pyrolyze on the injection port, and processes the optimized separation of each component of the pyrolyzed products.

The invention discloses a method for measuring dimethyl fumarate in a product by gas chromatography-mass spectrometry. The method comprises the following steps of: pretreating a dimethyl fumarate product to be detected by using an ultrasonic extraction method; setting the temperature of a sample injection port of a gas chromatography-mass spectrometer to be 240-280 DEG C, a flow rate to be 0.8-1.5 ml / min and the temperature of a port to be 280-300 DEG C, and selecting a weak polar column for a chromatographic column; enabling a sample to enter the chromatographic column through the sample injection port, and carrying out temperature programming on the temperature of the chromatographic column to separate the components of the sample by the chromatographic column; and enabling the components separated by the chromatographic column to enter a mass spectrometric detection part through the port of the gas chromatography-mass spectrometer, wherein an electron impact ion source is adopted as the ion source of the mass spectrometric detection. The method for measuring the dimethyl fumarate in the product by the gas chromatography-mass spectrometry has low detection limit, good detection effect, little consumption of analysis solvent and low detection cost.

The invention provides a method for detecting polycyclic aromatic hydrocarbon in food contact material by gas chromatogram-mass spectrometry coupling technique, comprising: Soxhlet extraction method or ultrasonic extraction method is used for extracting the detected food contact material; the extract sample is detected by a gas chromatogram-mass spectrometry coupling instrument; the temperature of a sample inlet of the instrument is set to be 240-320 DEG C, and the flow rate of carrier gas is set to be 0.5-2.0ml / min; a weakly polar chromatographic column is adopted, and the interface temperature is set to be 180-300 DEG C; the pretreated sample enters into the chromatographic column through the sample inlet of the instrument for temperature programming, and the temperature is raised to be 270-330 DEG C from 70-100 DEG C; after being separated by the chromatographic column, all the components in the sample are detected by mass spectrum. The method has the characteristics of low price of the detection instrument, safety, accurate and rapid analysis method and little interference as well as being suitable for standard analysis and detection which can lead all the components of the polycyclic aromatic hydrocarbon in the sample to be cracked in a mass spectrum ion source and optimize all the components of the cracked product, etc.

The invention provides a method for detecting the type and content of monosaccharide and oligosaccharide in edible mushroom, which is a method for measuring and analyzing by an ion chromatographic electrochemical detection means. The ion chromatogram obtained by the method can be used for determining the type and content of the monosaccharide in the edible mushroom according to peak migration time and peak area. The method realizes the accurate control over the monosaccharide and oligosaccharide components in edible mushroom.

The invention discloses a food-borne pathogenic bacteria detection immuno-sensor and a preparation method thereof. The method comprises the following steps of: performing array spreading on DNA, attaching gold sol particles to the skeleton of the DNA, modifying specific antibodies on a DNA conductive chain, immobilizing the specific immune protein antibodies by using the strong adsorption property of metal granules, and fixing the ordered array structure of the DNA on the electrode layer. The invention provides the accurate and quick analysis method; and the sensor is cheap, portable and easy for popularization and use.

Accurate, dependable methods for analyzing operational parameters of subsea control systems and diagnosis / prediction of failures are provided, in particular, methods for detection of leaking and / or clogging in hydraulic control system using recorded pressure signals and evaluating response communication strength (signal amplitude) of field equipment from, for example, subsea control systems. Prediction of failure(s) allows an opportunity to prepare for intervention to minimize the impact of failure before failure occurs, for example, by ordering equipment, tools and / or scheduling an intervention vessel. Similarly, diagnosing a failure drastically shortens the intervention time.

The invention relates to a detection method of halogenated alkyl phosphate and includes the following steps: samples are pre-treated with a Soxhlet extraction method or a supersonic extraction method; a high-performance liquid phase color spectrometer which connects diode array detectors is used for detecting the halogenated alkyl phosphate, and the proportions of the organic flow phases of the spectrometer are set from 50 to 100 percent, and the proportions of the inorganic flow phases are set from 0 to 50 percent, and the flow rates are set from 0.5 to 1.0ml per minute and the injection volume is set from 10 to 40ul and an anti-phase chromatographic column is selected as the chromatographic column; the samples pre-treated are brought into the chromatographic column by the flow phases of the high performance liquid phase color spectrometer, and the temperature of a column temperature box is set from 20 to 40 DEG C and components of the samples are separated from the chromatographic column; the components of the samples separated by the chromatographic column enter the diode array detectors to be detected. The detection method of the invention can prevent the samples from decomposing and is accurate and secure in analysis method.

The invention discloses a biological immune sensor and a detection method thereof, which is a novel sensor technology achieving electrical signal detection of pathogen in foods mainly through an immune chemical reaction principle of specificity between an antibody and an antigen. The detection method of the biological immune sensor is accurate and fast, and a product of the biological immune sensor and the detection method of the biological immune sensor is cheap, portable and easy to popularize.

The invention relates to the technical fields of separation and analysis and particularly discloses a preparation method and application of a magnetic diethylstilbestrol molecularly-imprinted polymer based on an organic-inorganic hybridizing technology. The preparation method comprises the steps of preparing ferroferric oxide particles by using a coprecipitation method; preparing silanized ferroferric oxide by using a stober method; preparing an organic and inorganic hybrid magnetic diethylstilbestrol molecularly-imprinted polymer by using a bulk polymerization method; and grinding the polymer, sieving, adding an eluent to extract and elute, and then, drying to obtain the magnetic diethylstilbestrol molecularly-imprinted polymer. A target product, namely diethylstilbestrol, can be rapidly combined on the surface of the magnetic diethylstilbestrol molecularly-imprinted polymer synthesized by using the preparation method and can be rapidly separated from a reaction system under the action of an external magnetic field, so that the aim of efficiently separating a trace amount of diethylstilbestrol from a complex matrix at high specificity is achieved, and the sample pretreatment efficiency is greatly increased.

The invention relates to a method for automatic and comprehensive online analysis of genome sequences. The method comprises the following steps of 1, uploading sample data; 2, analyzing the sample data; 3, querying an analysis result of a single sample; 4, conducting combination analysis of multiple samples; 5, querying a combination analysis result. According to the method for the automatic and comprehensive online analysis of the genome sequences, an innovative mode of gene sequence data management is put forward, and not only can gene sequence data of multiple human individuals be stored simultaneously, but also it can be achieved that the gene sequence data corresponds to basic information of the individuals; a more accurate, faster and more comprehensive analysis method of the genome sequences is put forward, and the more complete annotation of genetic information is achieved; a novel, personalized and visualized online display mode of analysis results is put forward, and the method is suitable for ordinary people and doctors or research personals related to biomedicine and can well meet the needs of practical application.

The invention relates to a method for simultaneously measuring contents of 10 chemical components in a four-substance soup decoction by an HPLC-DAD (high performance liquid chromatography-diode array detection) method and belongs to the field of traditional Chinese medicinal component analysis. The method comprises the following steps of (1) preparation of a mixed reference substrate solution; (2) preparation of a test substance solution; (3) measurement method: measuring the concentrations of a mixed reference substance and a test substance by the HPLC-DAD; the chromatographic conditions are that the chromatographic column is elit C18 (250*4.6mm, and 5 microns), the detection wavelength is 280nm, the flowing speed is 0.8mL / min, the column temperature is 30 DEG C, and the sample injection amount is 20 microliters; the gradient elution conditions are that isocratic elution is executed by using 2% methyl alcohol by volume for 0-2.0min, the methyl alcohol is linearly increased to 20 percent when isocratic elution is executed for 2.0-15.0min, and the isocratic elution is executed by using 20% methyl alcohol for 15.0-25.0min; the methyl alcohol is linearly increased to 100 percent when isocratic elution is executed for 25.0-42.0min, and the isocratic elution is executed through 100% methyl alcohol for 42.0-45.0min. The analysis method for simultaneously measuring the 10 chemical components in the four-substance soup decoction is simple, convenient and high in repetitiveness and is accurate and reliable; a basis is supplied to quality control on the four-substance soup decoction.

The invention discloses a method for measuring bisphenol A in a product by gas chromatography-mass spectrometry. The method comprises the following steps of: soaking and extracting bisphenol A in a sample with an organic solvent, and then carrying out silanization and derivatization; detecting the bisphenol A in the sample with a gas chromatography-mass spectrometer: setting the temperature of a sample injection port to be 250-300 DEG C, a flow rate to be 0.8-1.5ml / min and the temperature of a port to be 280-300 DEG C; enabling the sample to enter the sample injection port, carrying out temperature programming on the temperature of the chromatographic column from 40-60 DEG C to 250-320 DEG C; and enabling the sample to enter a mass spectrometric detection part through the port to carry out mass spectrometric detection, wherein an electron impact ion source is adopted as the ion source of the mass spectrometric detection, the impact energy of the ion source is 70eV, and the temperature of the ion source is set to be 230-250 DEG C. The method for measuring the bisphenol A in the product has low detection limit, good detection effect, little consumption of analysis solvent and low detection cost.

The invention relates to a method for detecting tripolycyanamide in an aquatic product via pressurized capillary electrochromatography, which comprises the steps of: 1) sample preparation; 2) sample pretreatment: centrifugal extraction of a sample by mixed solution of trichloroacetic acid with the mass concentration of 0.8-1.2 percent and acetonitrile at the volume ratio of (1.5-2.5):1, purification by an MCX (methoxycinnamate) solid-phase extraction column, and filtration by a filter film of 0.20-0.24mum for determination via the pressurized capillary electrochromatography; 3) preparation of standard tripolycyanamide solution; 4) analysis via the pressurized capillary electrochromatography; and 5) detection and analysis of the sample, quantitative analysis according to the retention time, and then quantitative analysis in an external marking method according to the peak area. The analytical method is efficient, accurate and highly sensitive, and the demands of drug detection of the tripolycyanamide in the daily aquatic product can be satisfied.

The invention provides a preparation method of an adsorbent material. The preparation method comprises the following steps: A), activated carbon fiber is impregnated in hydrogen peroxide and then washed; B), the activated carbon fiber obtained in the step A) is impregnated in an alkaline solution and washed, and the alkaline solution adopts a potassium hydroxide solution or a sodium hydroxide solution; and C), the activated carbon fiber obtained in the step B) is aged under protection of nitrogen to obtain the adsorbent material. According to the preparation method, hydrogen peroxide and the alkaline solution are adopted sequentially to modify the activated carbon fiber, so that basic groups in the activated carbon fiber are increased, and the adsorbability of the activated carbon fiber for formaldehyde, NO2, SO2, benzene and toluene is reinforced. The invention further provides an analytical method for pollutants in air by using the adsorbent material. With adoption of the analytical method, formaldehyde, NO2, SO2, benzene and toluene in the air can be analyzed simultaneously, and the accuracy is higher.

The invention discloses a method for quantitatively determining phenolic acid compounds in barley grains. The method comprises the following steps of: aiming at the physicochemical properties of phenolic acid, extracting the phenolic acid compounds from the barley grains by using a methanol solution at a certain concentration; performing centrifugation on extract; concentrating and filtering the extract; loading the prepared sample extract; and eluting and separating the prepared sample extract by using a methanol-methane acid aqueous solution. The analytical method is accurate, simple and convenient, has high sensitivity, is high in selectivity and repetitiveness; by the method, the types of the phenolic acid compounds in the barley grains can be comprehensively tested at one time; and compared with the conventional method, the method has the advantage that: analysis time is greatly shortened, so that basic requirements for quickly determining and evaluating the phenolic acid compounds in the barley grains on a large scale during production can be met; and the method is suitable for grains of any barley variety.

The invention relates to a detection method for 2-methoxyethanol, 2-ethoxyethanol, 2-methoxyethanol acetate and 2-ethoxyethanol acetate, comprising the following steps: pretreating a sample with Soxhlet<,>s extraction method or ultrasound extraction method; detecting 2-methoxyethanol, 2-ethoxyethanol, 2-methoxyethanol acetate and 2-ethoxyethanol acetate with a gas chromatograph providing with a hydrogen flame ionization detector, with the injector temperature of 180-250 DEG C, high purity nitrogen as carrier gas, the carrier gas flow rate of 0.8-1.5ml / min, and polar column as chromatographic column; bringing the pretreated sample in the chromatographic column through the gas chromatograph for programming temperature from 40-80 DEG C to 220-240 DEG C; and separating the four objects from the chromatographic column. The method has the advantages of cheap detector, simple and safe operation, accurate and rapid analytical method.

The invention relates to a method for identifying bee pollen based on kaempferol 3-O-beta-D-glucose-(2-1)-beta-D-glucoside. The method comprises the following steps: preparing a standard stock solution and a standard working solution, pretreating bee pollen, and detecting by using a liquid chromatogram-tandem mass spectrometry method. The detection result of the method shows that the standard curve relevance coefficient is greater than 0.9990, the addition recycling rate ranges from 73.1 percent to 98.4 percent, the relative standard error is less than 6.1 percent, the detection limit is 0.1mu g / g, and the quantitation limit is 0.3mu g / g. The result shows that the established extraction method and an instrument analysis method are accurate and stable and applicable to qualitative and quantitative analysis on kaempferol 3-O-beta-D-glucose-(2-1)-beta-D-glucoside.

The invention discloses an atmospheric environment chloride ion deposition rate testing device and method. The method comprises the steps of chloride ion deposition, chloride ion dissolution, chlorideion titration and blank sample determination, the chemical reagent silver nitrate used in the whole test process is low in toxicity, highly toxic and highly corrosive dangerous chemicals used in an existing method are avoided, and the test operation safety is high. The titration process is automatic, simple in flow and convenient to operate. The method can greatly save the test time, has high accuracy, reliability and safety, can quickly analyze and test a large amount of to-be-tested gauze in a short time, and improves the working efficiency of power grid atmospheric corrosion map construction of the State Grid Corporation of China.

The invention provides a method for acquiring the logged-on user password from memory mirroring documents of a 64-bit Windows operation system. The method comprises the following steps: (a) acquiring version information of a system; (b) acquiring the value of a PEB structure variable from aCR3 register and a process environment block of lsass.exe process; (c) dumping execution samples of dynamic link library lsasrv.dll and tspkg.dll; (d) acquiring key related data; (e) acquiring user information from lsasrv.dll; (f) acquiring a login user master certificate from the tspkg.dll dumping document; and (g) acquiring the password. The method for acquiring the logged-on user password plaintext is accurate and efficient, has the analysis effect not influenced by password complexity, and is an important means for acquiring user login information from a physical memory mirroring document; and the acquired login user password is an important evidence in computer online evidence collection.

The invention discloses a precise determination method of extreme working conditions of external heat flow of an orbit of a remote sensor in a whole life cycle, and belongs to the technical field of precise heat control of spatial optical remote sensors. The method specifically includes: 1), selecting parts, which are on a satellite and block the external heat flow of a light entrance of the remote sensor, and parts which are inside the remote sensor and in radiation heat exchange with an optical lens, ignoring radiation, heat capacity and heat conductivity of the back of the optical lens, andestablishing a finite-element heat model of the remote sensor; (2), adopting heat analysis software to calculate temperature of all finite-element nodes of the finite-element heat model of the remotesensor in the whole life cycle according to the preset orbit, and extracting temperature of each finite-element node of the optical lens of the remote sensor in the whole life cycle therefrom; and (3), calculating external heat flow absorbed by each finite-element node of the optical lens of the remote sensor in the whole life cycle according to temperature of the optical lens of the remote sensor in the whole life cycle, and selecting extremum values of the external heat flow to determine the extreme working conditions of the external heat flow of the orbit of the remote sensor in the wholelife cycle. According to the method, calculation is comprehensive, efficiency is high, and precision is high.

The invention relates to a method for analyzing aluminum alloy oxidization solution, and is characterized in that the method comprises the following steps: analyzing the sulfate radical content, analyzing the oxalic acid content, analyzing the tartaric acid content and analyzing the free acidity, the total acidity and the aluminum content. The method has the advantages that firstly, a more accurate and convenient and simpler analysis method is obtained; and secondly, through the adjusted analysis method, the relative measurement errors of sulfuric acid, oxalic acid and tartaric acid concentrations are respectively reduced from 20 percent, 5 percent and 20 percent to 1-4 percent, 0.05-3 percent and 2-4 percent. Meanwhile, the invention also provides a simple and feasible method for analyzing the free acidity, the total acidity and the Al3+content and a method for replenishing and maintaining work bath solution. The measurement results obtained through the analysis method meet the technological formula requirements. The method can be used by enterprises to measure the concentration of each component of the bath solution in a sulfuric acid and oxalic acid oxidization system or a sulfuric acid, oxalic acid and tartaric acid oxidization system. The analysis method is simpler to operate and has high practicability and accuracy.

A DEM-based topographic slope analysis method disclosed by the present invention comprises the steps of combining different resolutions based on the DEM data, and calculating and extracting the slopedata of a raster matrix within a certain territorial scope; aiming at the concrete requirements of the topographic slope, dividing the grades of the slope requirements according to the rules, respectively comparing with the actual slope data matrixes to obtain a plurality of comparison result matrixes, fusing and superposing the comparison result matrixes to generate the slope requirement matrixes, and then distributing the colors according to the element values in the comparison result matrixes to fill, and generating a vector diagram; and finally adopting a projection algorithm to convert the vector diagram to obtain a slope analysis vector diagram satisfying a projection mode. The present invention provides a more visual and accurate topographic display form and analysis method for themilitary and civil fields having certain requirements for the topographic slope fluctuation, such as the helicopter landing, the search and rescue, the path planning, etc.

The invention provides an analytic identification method for identifying that whether samples comprising a ginkgo leaf preparation, foods, healthcare products, medicines and / or cosmetics containing ginkgo leaf extracts and the like contain proanthocyanidins having other sources. The method is characterized in that a sample to be detected and a standard substance are pretreated through purifying with an polyamide resin, extracting with an organic solvent and the like; normal phase-high performance liquid chromatograms of the solution sample of the ginkgo leaf preparation to be detected and the solution substandard substance of a standard ginkgo leaf preparation are respectively established by adopting a phenomenex dihydric alcohol as a stationary phase, adopting a column having parameters of 250*4.6mm and 5mum, adopting (A)acetonitrile-(B)methanol / water / acetic acid (95 / 3 / 2, V / V / V) as a mobile phase, and adopting gradient eluting; and the chromatograms are contrasted and analyzed. The identification method has the advantages of high sensitivity, good resolution and reappearance, and obvious identification characteristic, and can accurately identify if the ginkgo leaf is added with above 0.5% of the proanthocyanidins having the other sources.

The invention relates to the field of analytical chemistry, specifically to an infrared spectroscopic analysis and identification method for the polypide of Cordyceps sinensis. The objective of the invention is to overcome the technical problem that whether the polypide of Cordyceps sinensis is true or false is difficult to determine at present. Thus, the invention provides the method for rapid and accurate discrimination of the polypide of Cordyceps sinensis. The method comprises the following steps: a, drafting the standard spectrum of the polypide of Cordyceps sinensis; b, acquiring necessary infrared spectroscopic characteristic peaks and common infrared spectroscopic characteristic peaks of the polypide of Cordyceps sinensis; and c, comparing infrared spectroscopic characteristic peaks and infrared spectroscopic similarity of a detected sample of the polypide of Cordyceps sinensis. The invention provides the novel method for rapid and accurate discrimination of the polypide of Cordyceps sinensis.

The invention discloses a method for measuring ethanolamine substance residual quantity in cosmetics. The method comprises the following steps of detecting a sample which is subjected to liquid-liquid extraction by using high performance liquid chromatography-tandem mass spectrometry instrument (HPLC-MS / MS), adding a formic ethanol solution in the sample, uniformly mixing in a volution manner, carrying out ultrasound extraction and centrifugal separation, taking a supernatant fluid and detecting by using the HPLC-MS / MS. The liquid chromatography conditions are that an amino liquid chromatography pillar is adopted, the column temperature is 30-60 DEG C, sample volume is 10-20mu L and the flowing speed of a flowing phase is 0.15-0.60mL / min; and the MS / MS conditions include an electric atomizing ion source, an cation mode ionization and a multi-ion reaction monitoring mode (MRM). The method provided by the invention has the characteristics that the extraction and purification are rapid, the selectivity of the method is high, the specificity of a chromatogram is strong, the interference is small, and the detection limit is low.