159 results about "Matrix assisted laser desorption ionization time of flight" patented technology

The invention relates to a synthetic method for a magnetic metal organic framework composite material coated by [Cu2(btc)2] on surfaces of ferroferric oxide microspheres and application of the composite material. The method comprises the following steps of: firstly synthesizing ferroferric oxide microspheres by a hydrothermal synthesis method; dispersing magnetic spheres in an ethanol liquid of mercaptoacetic acid, wherein hydroxyls are formed on the surface of the spheres; dispersing mercaptoacetic acid modified magnetic spheres to an ethanol liquid of copper acetate, reacting for 15 minutes at 70 DEG C, and then dispersing the product in an ethanol liquid of trimesic acid and reacting for 30 minutes at 70 DEG C; and performing alternate reaction of magnetic spheres with copper acetate and the ethanol liquid of trimesic acid to finally, obtain the magnetic metal organic framework composite material with a core-shell structure. The material has a metal organic framework shell layer and can be coordinated with peptide fragments with amino groups and carboxylic group so as to enrich low concentration peptide. Meanwhile, the enriching and separating process is fast, simple and convenient due to high paramagnetism of ferroferric oxide. The synthetic method is simple and low in cost, and can be used for enrichment and separation of low abundance peptide fragments less than 1nM and MALDI-TOFMS (Matrix-Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometer) detection.

The present invention provides for methods of quantitating the amounts of proteins or peptides, including those that are closely related isoforms, using matrix-assisted laser desorption / ionization time of flight mass spectrometry (MALDI-TOF-MS). Measurement of protein concentrations in vivo has been extremely difficult and problematic, and protein concentrations have not been shown to correlate well with mRNA levels, the standard used in the past. The present invention overcomes the deficiencies of prior methodologies by taking advantage of MALDI-TOF-MS technology and applying it to proteins and peptides in a way that allows for accurate, quantitative measurement in vivo of protein or peptide concentrations.

The present invention discloses a graphene matrix and an application of the graphene matrix in matrix-assisted laser desorption / ionization-time of flight-mass spectrometry (MALDI-TOF-MS) detection. According to the present invention, in the MALDI-TOF-MS, the graphene is adopted as an assisted matrix, such that the analysis and the detection of the materials including from the small molecule compounds to the biological macromolecules can be efficiently and rapidly achieved; importantly the background interference of the molecular ion peak of the traditional organic matrix can be effectively eliminated so as to achieve the analysis and the detections of amino acids, lipid compounds, peptides, proteins, oligonucleotides, and other structural molecules; the MALDI-TOF-MS adopting the graphene as the matrix is the desorption ionization method, which does not require addition of any organic matrixes, such that the decomposition of the analyte can be avoided, and good reproducibility and high salt tolerance are provided; the efficient and rapid detection method is provided for the natural products and the biological metabolites; the method further can be used for the detection of the common biological macromolecules, and can be popularized and applied in all the MALDI-TOF mass spectrometry so as to achieve the deep application of the graphene.

The invention belongs to the field of nanotechnology, and particularly relates to a synthetic method and application of a polydopamine-modified carbon nanotube composite material. The synthetic method comprises the following steps in sequence: dispersing carbon nanotubes into dopamine-containing aqueous solution; quickly adding trismetyl aminomethane buffer solution into the dopamine-containing aqueous solution in which the carbon nanotubes are uniformly dispersed under magnetically stirring; mechanically stirring for 10 hours at room temperature; washing by water; and centrifugally separating to obtain the carbon nanotube composite material of which the surface is modified by polydopamine, wherein the carbon nanotube composite material shows high dispersibility in water. The polydopamine-modified carbon nanotube composite material adopts the carbon nanotubes as the framework, and therefore, a large specific surface area is provided; the polydopamine-modified carbon nanotube composite material is excellent in environmental stability and biocompatibility and high in dispersibility in water; the synthetic method is simple and low in cost; and the polydopamine-modified carbon nanotube composite material can be used as the substrate for analyzing metabolite micromolecule under high-throughput MALDI-TOFMS (Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry).

The invention discloses a preparation method of graphene covered silica gel. The method comprises the following steps of: firstly adsorbing graphene oxide on the surface of amino silica gel through an electrostatic adsorption effect; and then carrying out hydrothermal reduction treatment to obtain a material of the graphene covered silica gel. The material has a simple preparation method, is safe and environment-friendly, and has good reproducibility. The material obtained by the preparation method has high graphene content; the prepared graphene covered silica gel material is used as a filler of solid phase extraction (SPE) so as to have the higher adsorption amount when being compared with a document value; and the material is used for a desalting step of enriching peptide in a bovine serum albumin (BSA) enzymolysis solution and analyzing a matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOFMS), so as to obtain the better effect.

This invention discloses one metal chelate nanometer magnetic balls and its process method and application, which comprises the following steps: using metal salt and surface to cover hydroxyl group nanometer magnetic ball as main materials to complex metal ion to get the magnetic ball; then using body liquid to extract protein and polypeptide by use of magnetic field; the protein polypeptide for basic aid laser to absorb fly time mass spectrum and electrical spray mass spectrum for analysis.

The invention discloses application of a molybdenum disulfide / nanosilver composite serving as a matrix to MALDI (matrix-assisted laser desorption / ionization) time of flight mass spectrometry. Few-layer molybdenum disulfide is prepared according to an improved chemical lithium ion intercalation and exfoliation method, on the basis of which the molybdenum disulfide / nanosilver composite is prepared through in-situ reduction of silver nitrate. An analysis method taking molybdenum disulfide / nanosilver composite as an MALDI matrix is applicable to mass spectrometry of micromolecules with molecular weight smaller than 1000 and suitable for molecules of amino acids, oligopeptides, fatty acids, alkaloids, hormones, antibiotics, antibacterial drugs, anticancer drugs and the like. Matrix background interference is avoided when the method is adopted for detection of molecules with a mass-to-charge ratio (m / z) smaller than 1000. The method can be effectively applied to fields of organic and biomass spectrometry, imaging mass spectrometry, protein mass spectrometry, metabonomics, biomarker discovery, environmental analysis and the like.

The invention discloses application of naphthylethylenediamine inorganic acid salt or naphthylethylenediamine organic acid salt as a matrix in MALDI MS (matrix-assisted laser desorption / ionization mass spectrometry). In the application, the MALDI MS is MALDI-TOF MS (matrix-assisted laser desorption / ionization - time-of-flight mass spectrometry); the naphthylethylenediamine inorganic acid salt is naphthylethylenediamine hydrochloride, naphthylethylenediamine nitrate, naphthylethylenediamine phosphate or naphthylethylenediamine sulfate; and the naphthylethylenediamine organic acid salt is naphthylethylenediamine trifluoroacetate, naphthylethylenediamine acetate, naphthylethylenediamine formate, naphthylethylenediamine citrate or naphthylethylenediamine oxalate. The invention technically overcomes the defect that small-molecule samples cannot be effectively analyzed because serious matrix background interference is apt to be caused in a low molecular weight zone when organic small-molecule matrices are commonly used. The matrix used by the invention is not required to be added with ionizing reagent and the requirements on sample treatment are reduced; and since background interference hardly exists within a testing range (m / z: 0-1000), kinds of complex mixed systems can also be analyzed by using the matrix.

The invention discloses a complete-set primer for SNP (Single Nucleotide Polymorphism) sites of drug-metabolizing enzyme genes and application thereof. The complete-set primer comprises amplificationprimers and extension primers of 9 SNP sites of 7 drug-metabolizing enzyme associated genes of human genome DNA, wherein a pair of multiple PCR amplification primers and a single-base extension primerare respectively designed for each site, and an MALDI-TOF MS (Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry) method is adopted to detect typing of the SNP sites of a sample to be detected. The complete-set primer disclosed by the invention has the beneficial effects that a detection method for the drug-metabolizing enzyme genes based on gene molecule typing is established, and the typing of multiple SNPs can be finished at the same time in the same reaction, so that the accurate and efficient effects are achieved and the cost is low; the covered genes and sitesare related to the metabolizing enzyme genes related to 8 major types of common drugs for children, and the coverage is most complete in gene detection products of safe drugs used for children so far.

The invention discloses a method for separating and identifying glycoprotein N-sugar chain structure, and belongs to the technical field of sugar chain detection. According to the method, concanavalin (ConA) is used to separate and enrich high-mannose type and non-high-mannose type N-sugar chains; matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF-MS) is used to detect; a signal-to-noise ratio of 6 is used as a threshold value to carry out data screening; and a Glycoworkbench software is used to analyze. Structure shows that 23 N-sugar chains are identified from a reference group; 29 N-sugar chains are identified from two parts of the high-mannose type and non-high-mannose type; and the identified N-sugar chains are six more than that before ConA enrichment. The method has higher sensitivity and more abundant sugar chain information and has obvious advantage for identification of low kurtosis sugar chains.

The invention relates to the field of utilization of coal liquefaction residue to produce carbon fibers, and discloses spinnable asphalt prepared from coal liquefaction residue, and a preparation method thereof, and carbon fiber. According to the present invention, through matrix-assisted laser desorption ionization time-of-flight mass spectrometry, the determination results show that the number average molecular weight of the spinnable asphalt is 600-1000, and the weight average molecular weight of the spinnable asphalt is 700-1200; through element analysis, the results show that the ratio ofthe C atom to the H atom in the spinnable asphalt is (1.4-1.6):1, and based on the total amount of the spinnable asphalt, the oxygen content is 1.8-2.7 wt%, and the hydrogen content is more than 4.5wt%; and the spinnable asphalt is produced by using the coal liquefaction residue, and the carbon fiber is prepared.

The invention is directed to a method for detecting low concentrations of bacteria in liquid solution that may or may not be complex liquid solutions. In one embodiment, immunomagnetic separation (IMS) is used to separate target bacterium that may be in a liquid mixture from other constituents in the mixture. A low concentration of a bacteriophage for the target bacteria is subsequently used to infect target bacterial cells that have been captured using the IMS technique. If at least a certain concentration of target bacterium are present, the bacteriophage will multiply to a point that is detectable. Matrix assisted laser desorption ionization / time-of-flight-mass spectrometry (MALDI / TOF-MS) is then used to produce a mass spectrum that is analyzed to determine if one or more proteins associated with the bacteriophage are present, thereby indirectly indicating that target bacterium were present in the liquid mixture.

The invention provides a peptide identification method by using a mesoporous silica composite combined with mass spectrum. A composite with perfluoroalkyl group modified mesoporous silica covering on the surface of Fe3O4 magnetic microsphere is used in matrix-assisted laser desorption ionization-time of flight mass spectrometric analysis of perfluoroalkyl group derived peptide. The material shows extremely strong affinity with the fluorous phase derived phosphorylated peptides, while maintaining good dispersion in aqueous solution. The Fe3O4 magnetic core in the material simplifies the process of enrichment and separation. A solid phase microextraction method based on the composite with perfluoroalkyl group modified mesoporous silica covering on the surface of Fe3O4 magnetic microsphere achieves selective enrichment of non-phosphorylated peptides, and can be successfully applied to the enrichment of endogenous phosphopeptides in human serum.

The invention provides a method for quickly and accurately identifying microorganism in a sample. The method comprises the following steps: establishing a pure microorganism reference fingerprint mass spectrum library, and using the pure microorganism reference fingerprint mass spectrum library as a standard spectrum; selectively capturing microorganism from the sample containing complicated background matrix by utilizing a functional material; analyzing the microorganism captured by the functional material by using an MALDI (Matrix-Assisted Laser Desorption)-TOF (Time of Flight)-MS (Mass Spectrometry), thus obtaining a microorganism spectrum; comparing the obtained microorganism spectrum with the standard spectrum, and realizing microorganism identification. The method for quickly and accurately identifying the microorganism in the sample, provided by the invention, has a function of extracting and enriching the microorganism in the sample; through an enrichment function, the lowest detection limit of a mass spectrometer is greatly reduced, and the detection sensitivity is increased; microorganism identification is fast, the selectivity is high, the sensitivity is high, and the usage of the sample is less and is just 1 mL.

The invention provides a 96-well high-throughput solid-phase extraction device for mass spectrographic analysis. The device comprises a silicone seal cover plate, joint extraction column holes, a 96-well joint extraction column plate, an upper sieve plate, a lower sieve plate, a solid-phase extraction column packing, a 96-well sample collection plate and sample collection holes. According to the extraction device, a 96-well solid-phase extraction plate packed with the corresponding packing is utilized, a vacuum negative-pressure device or gravity centrifugation is connected, which is used for extracting high-throughput protein or polypeptide from the body fluid or biological sample lysate and directly used for matrix-assisted laser desorption ionization time-of-flight mass spectrometry and electrospray ionization mass spectrometry. By the extraction device, the solutions including protein or polypeptide extracted from multiple body fluid or biological sample lysate can be directly used for mass spectrometric detection without extra steps including drying, collection, dissolution and so on. During the whole process, the operation is simple and convenient, rapid and high-throughput. The extraction device has excellent application value in the pretreatment of high-throughput biological sample of mass spectrometry.

The invention discloses an application of a nitrogen-doped carbon point to analysis of micro-molecular environmental pollutants, and particularly relates to the application taking the nitrogen-doped carbon point (N-CDs) as a matrix of a matrix-assisted laser desorption ionization-time of flight time mass spectrometry (MALDI-TOF MS) to the analysis of the micro-molecular environmental pollutants. By taking the nitrogen-doped carbon point as the matrix, the analysis and detection on the micro-molecular environmental pollutants with the m / z ranging from 150 to 1000 can be efficiently and rapidly realized. Suitable micro-molecule types comprise hydroxyl polycyclic aromatic hydrocarbon, nitryl polycyclic aromatic hydrocarbon, bisphenol compounds, perfluoro-acid environmental pollutants and the like. When the nitrogen-doped carbon point is used as the matrix to detect micro-molecules, background interferences of a traditional organic matrix ion peak can be effectively eliminated; an ionization agent does not need to be added and the requirements on sample treatment are reduced; the nitrogen-doped carbon point has good reproducibility and high salt resistance; and an efficient and rapid detection method is provided for the environmental pollutants and an application range of the carbon point is expanded.

This invention relates generally to methods and apparatus for desorption and ionization of analytes for the purpose of subsequent scientific analysis by such methods, for example, as mass spectrometry or biosensors. More specifically, this invention relates to the field of mass spectrometry, especially to the type of matrix assisted laser desorption / ionization, time-of-flight mass spectrometry used to analyze macromolecules, such as proteins or biomolecules. Most specifically, this invention relates to the sample probe geometry, sample probe composition, and sample probe surface chemistries that enable the selective capture and desorption of analytes, including intact macromolecules, directly from the probe surface into the gas (vapor) phase without added chemical matrix.

The invention discloses a novel method for identifying Shigella sonnei by using MALDI-TOF-MS. The invention provides an identification method for distinguishing whether a to-be-detected strain is Shigella sonnei or other batacteria. The invention also discloses application of a set consisting of a MALDI-TOF-MS detection instrument, a reagent for the MALDI-TOF-MS detection instrument and a readable carrier. The readable carrier can record the following conditions: if protein peaks obtained after detection of the to-be-detected strain by using MALDI-TOF-MS contains the four characteristic protein peaks with mass-charge ratios of 5612.81 + / - 8.7, 4871.12 + / - 45.9, 4164.03 + / - 26 and 3247.05 + / - 6.9, respectively, the to-be-detected strain is Shigella sonnei or candidate Shigella sonnei. Experimental results prove that MALDI-TOF-MS has good accuracy and specificity in identification of Shigella sonnei and shortens identification time.

The invention relates to a primer combination and a kit for identifying flue-cured tobacco Zhongyan 100, application and a detection method, and belongs to the technical field of tobacco variety identification. According to the primer combination and the kit for identifying the flue-cured tobacco Zhongyan 100, application and the detection method, a 420K Tobacco SNP array is utilized to conduct whole-genome SNP typing on the mainly-planted varieties of tobacco in our country in recent years, a set of specific SNP markers suitable for identifying the flue-cured tobacco Zhongyan 100 are obtained through screening according to intervarietal polymorphic SNP sites, wherein the number of the specific SNP markers is thirteen; thirteen SNP site flanking sequences obtained from a reference genome of cultivated tobacco are aligned, the sequences are as shown in SEQ ID NO: 1-13, and primers are designed based on the sequences; and the sites are subjected to typing detection by utilizing the designed primers and adopting a matrix-assisted laser desorption-ionization time of flight mass spectrometry technology. An SNP typing result is obtained according to a detection result, and whether a sample is the Zhongyan 100 or not is identified. By adopting the detection method, the needed detection sample amount is small in the detecting process, the detection throughput is high, and the identification result is accurate.

The present invention relates to a new use for matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF MS). Specifically, the present invention provides a new method for evaluating the aminoacylation state of tRNAs, which are useful for site-directed mutagenesis of both sidechain and backbone protein structures. Further, the present invention useful for the generation of novel peptides, polypeptides, and proteins that may be used in drug design and screening, and in the design of small molecule agonists or antagonists for receptors, enzymes and other proteins and molecules involved in various disease states. Additionally, the present invention is useful in the field of tRNA aminoacylation, particularly in the design of synthetases.

The invention discloses a method for detecting pathogenic vibrios by MALDI-TOF-MS (Matrix Assisted Laser Desorption Ionization-Time-Of-Flight-Mass Spectrometry). The method comprises the following steps: acquiring MALDI-TOF-MS data information of a strain to be detected, and comparing the MALDI-TOF-MS data information with acquired information in an MALDI-TOF-MS database so as to obtain an identification result, wherein the MALDI-TOF-MS database is a database including MALDI-TOF-MS data information of selected microorganisms, and the selected microorganisms are microorganisms with strain numbers of 1-128 in a table 1. The invention also provides an MALDI-TOF-MS database, and a newly added base strain comprises 128 common pathogenic strains, which are wide in strain source; the constructed MALDI-TOF-MS strain database is large in amount of information. By using the constructed data, detection and identification of an unknown strain can be realized with high sensitivity, high specificity, high speed, high efficiency and high flux.

The invention discloses a microorganism identification and typing method in combination with mass spectrums and FTIR spectrums based on matrix-assisted laser desorption ionization flight time. The method comprises the following specific steps: (1) respectively collecting microorganism characteristic mass spectrums and infrared absorption spectrums; (2) preprocessing the collected characteristic mass spectrums and infrared absorption spectrums; (3) performing data fusion on the data of the preprocessed characteristic mass spectrums and infrared absorption spectrums; and (4) carrying out clusteranalysis on the fused data of the mass spectrums and the infrared absorption spectrums to realize identification and typing of microorganisms. A data set used for microbial typing contains more characteristic biological information, and effective distinguishing of extremely similar strains difficult to distinguish by simple means, such as Escherichia coli and Shigella, can be realized.

The invention belongs to the technical field of molecular biology and medical examination, and relates to a matrix-assisted laser desorption ionization flight time mass spectrum method for simultaneously measuring signal channel series protein coding gene polymorphism of tacrolimus action targets of a person. The method comprises the following steps of performing multiple PCR (polymerase chain reaction) amplification after performing DNA (deoxyribonucleic acid) extraction on a sample; and performing genetic typing analysis on the sample by using a flight time mass spectrum method after single nucleotide primer extension. The method is easy and convenient to operate, a sequence specificity probe is not required, multiple detection on a plurality of samples can be implemented, 40 reactions can be realized by each system, 40 SNP (single nucleotide polymorphism) sites can be detected simultaneously, throughput is high, application range is wide, and tens of thousands of samples and dozens of to hundreds of sites can be detected simultaneously; fluorescent markers are not required, only common primers require to be synthesized, and analysis cost of a single sample is low; and flexibility is high, the amount of samples required for analysis is small, and sensitivity and detection precision are high. The method is suitable for detecting clinic conventional genes, and further provides a technical support for clinic individual rational drug use.

The invention discloses an MALDI-TOF-MS (Matrix-Assisted Laser Desorption / Ionization Time-of-Flight Mass Spectrometry) detection method of fluoroquinolone medicines in milk. The method comprises the following steps: sieving 8-hydroxyquinoline by a functional mesoporous molecular sieve to obtain SBA (Santa Barbara Amorphous material)-15-8-hydroxyquinoline; diluting milk by trifluoroacetic acid to obtain a sample target object; dispersing the SBA-15-8-hydroxyquinoline in ethanol liquor and carrying out ultrasonic treatment to obtain suspension liquid; adding the suspension liquid into the sample target object, and naturally drying at room temperature to obtain an MALDI matrix thin layer; placing milk to be detected on the MALDI matrix thin layer, carrying out MALDI-TOF-MS analysis after a solvent is naturally evaporated, and dropping a sample and the matrix on a target plate in a mixed manner, and detecting after the target plate directly enters into the MALDI-TOF-MS, wherein a fuzzy pre-treatment process is canceled. When the residual amount of the fluoroquinolone medicines in milk exceeds 0.05mg / kg, 18 of 25 fluoroquinolone medicines in milk can be effectively detected, so that the detection efficiency is greatly improved so as to meet the demand on quick test and quick release of import and export products.

The invention disclose a protein fingerprint atlas-spectrum model of acidovorax avenae subsp. citrulli, the model is drawn according to the mass-to-charge ratios of acidovorax avenae subsp. citrulli protein and wave crest strength coefficients thereof, wherein the mass-to-charge ratios comprises: 3171.4, 3735.0, 4963.5, 5139.0, 5866.4, 6554.1, 7466.1, 7948.0, 8384.5, 9304.2, 9504.3, 9920.0, 10272.8, 10840.7, 12530.5, and 12896.5. The invention also discloses a matrix-assisted laser desorption / ionization flying time mass spectrum detection method based on the model. The method can qualitatively detect whether a sample contains acidovorax avenae subsp. citrulli. The model has a function of specific recognition, is capable of being applied to commercial detection of acidovorax avenae subsp. citrulli, and is especially suitable for rapid and high throughout detection for departments such as port inspection and quarantine.

The invention discloses a protein fingerprint model for Burkholderia gladioli and application thereof. The model is drafted according to the mass-to-charge ratios of the protein of Burkholderia gladioli and the peak intensity coefficients of the protein, wherein the mass-to-charge ratios include 3568.4, 3864.3, 4802.0, 5233.8, 6829.7, 7133.9, 7422.1, 7701.7, 9602.7 and 10153.8. A detection method comprises the following steps: preparation of a sample protein chip; detection with matrix-assisted laser desorption ionization time-of-flight mass spectrometer; and comparison of the protein fingerprint of the sample. The protein fingerprint model can qualitatively detect whether a sample contains Burkholderia gladioli or not, can be used for detection of commercial Burkholderia gladioli and is especially applicable to departments like a port inspection and quarantine part with detection requirements for rapidness, high flux and the like.

The invention provides an R-CH2-PO3-M modified magnetic nanoparticle as a phosphorylation protein enrichment material, as well as a preparation method and application thereof in phosphorylation protein enrichment. The purpose of combining the functions of magnetic nanoparticles and phosphonic acid groups can be achieved through modifying carboxyl groups for organic phosphonic acid gene R. The synthesis method of the magnetic nano material with functionalized organic phosphonic acid is simple, rapid and green. The material has favorable enrichment effect on phosphorylation proteins, and an MALDI-TOF MS (Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry) can be used for detecting a phosphorylation peptide segment in 10-8M of bovine serum beta-casein digestive juice. The results show that a type of favorable phosphorylation protein enrichment materials can be constructed through combining the magnetic nanoparticles with the organic phosphonic acid.

The invention discloses a positioning method of a polypeptide disulfide bond. The comprises the steps that to-be-tested polypeptide is partially reduced in the solution environment of a disulfide bond containing reducing agent; the partially reduced polypeptide is alkylated in the solution environment of a polypeptide containing denaturing agent and an alkylated reagent; the alkylated polypeptide is completely reduced in the solution environment of the polypeptide containing denaturing agent and the alkylated reagent; a matrix auxiliary laser desorption ionization-flight time mass spectrum is used for performing molecular weight on products; samples qualified through detection are subjected to hygroplasm combination tandem mass spectrum detection, and mass spectrometric data is obtained; the spectrometric data is converted into a data format compatible with the mass spectrum identification software, then, the mass spectrum identification software is used for performing search comparison on the spectrum data and a reference polypeptide sequence database, and the proportion of the connecting position of the polypeptide disulfide bond and different connection modes is calculated. The method is small in sample amount requirement, low in purity requirement, easy to implement, high in repeatability, small in analysis difficulty, high in result accuracy, high in flux and low in cost.