122 results about "Daughter Ion" patented technology

A mass spectrometry system that includes first and second ion sources that produce ions, the ions produced by the second ion source being calibration ions to calibrate the mass spectrometry system; an ion transfer device that receives the ions as a continuous stream during a first time period and forms a first ion packet as a single ion packet, such that during a second time period when the ion transfer device delivers the first ion packet, it receives the ions as a continuous stream to form a second ion packet by accumulating the incoming ions in another single ion packet, such that the ion transfer device separately delivers the formed ion packets at a frequency in a range from 1 to 1000 Hz; and a mass analyzer that separates the ions in the ion packets based on the mass-to-charge ratio of the ions.

A direct-read precision de novo sequencing method for amino acid sequences of proteins and proteome, the method involving determining the type of product ions on the basis of lysine (K) and arginine (R) dual mass-defect amino acid encoding (NeuCode) labeling, and performing paired mirror digestion to achieve the direct-read precision de novo sequencing of animo acid sequences of proteins with full product-ion coverage. A protein is labeled with K / R NeuCode amino acids, mirror peptide fragments are obtained by means of paired mirror digestion, and the mirror peptide fragments are subjected to tandem mass spectrometry analysis to obtain a mirror spectrum with full product-ion coverage and product ion type identification. Consequently, the amino acid sequence information in a secondary spectrum can be directly read on the basis of the mass difference of two adjacent product ions of the same type, thereby realizing direct reading and precision sequencing of the amino acid sequence of the protein.

The mass spectrometer according to the present disclosure is a mass spectrometer that generates a group of product ions from a precursor ion derived from a sample component having a hydrocarbon chain and performs mass spectrometry thereon, and includes a reaction chamber, an electrode, an introduction unit, a mass separation unit, a detection unit, a power supply unit, and a controller. The controller performs mass spectrometry on the sample component while alternating between a first analysis mode in which ions are detected in a first polarity mode and in a multimode, and a second analysis mode in which ions are detected in a second polarity mode and in a single mode.

The invention discloses a method for detecting natural plant hormones and exogenous growth regulators of vegetables, efficient separation and accurate detection of the natural plant hormones and the exogenous growth regulators are realized through combination of hydrophilic interaction chromatography and mass spectrometry, a hydrophilic interaction chromatographic column is adopted, and conditions such as mobile phase composition and flow velocity are optimized; the selectivity of polar substances is improved by utilizing hydrophilic interaction, so that compounds with similar structures achieve baseline separation, and chromatographic peak overlapping interference is avoided; the mass spectrometric detection only responds to a specific ion signal by screening characteristic parent ion / daughter ion pairs of a target object, so that matrix impurities and non-target ion interference are effectively eliminated, the false positive risk is remarkably reduced, and the detection sensitivity and specificity are improved; the combined technology is combined with the efficient separation capacity of the hydrophilic interaction chromatographic column and a multi-reaction monitoring mode, synchronous separation of multiple compounds with similar polarities in single analysis is achieved, parallel detection of dozens of target objects is supported, and the analysis time is greatly shortened.

This invention relates to a method for detecting the activity of a toxin produced by bacteria of the families Peptostreptococcaceae or Clostridiaceae using mass spectrometry, which comprises the following steps: a) providing a planar surface suitable for mass spectrometry measurement, with attached affinity molecules; b) incubating the planar surface from step a) with the substrate of the toxin to be detected, to bind the substrate to the affinity molecules; c) subsequently incubating the planar surface from step b) with a sample in which the active toxin is to be detected, in the presence of a modification compound, and incubating it for a time sufficient for the substrate to react with the modification compound in the presence of the active toxin, if present in the sample, to form a modified substrate if the active toxin is present in the sample; d) removing the remnants of the sample; e) subjecting the (modified) substrate on the planar surface to matrix-assisted laser desorption / ionization, ionizing it and subsequently measuring the mass spectrum of the (modified) substrate; f) analyzing the measured mass spectrum, such that if the measured mass spectrum corresponds to the non-modified substrate, the active toxin is not present, and if the measured mass spectrum corresponds to the modified substrate or a mixture of the modified and non-modified substrate, then the active toxin is present in the sample. The invention further relates to a device for the soft landing of affinity molecule ions onto a planar surface suitable for mass spectrometry for carrying out step a) of the above method.

This invention discloses a method for determining the content and simultaneously identifying the source of polyglutamic acid (PCA) in fertilizers based on microwave digestion-high-resolution liquid chromatography-mass spectrometry (LC-MS), belonging to the field of analytical detection technology. The method includes: microwave-assisted acid hydrolysis of fertilizer samples to obtain a hydrolysate; injecting the hydrolysate into a liquid chromatography-high-resolution mass spectrometry (LC-MS) instrument, performing a single injection analysis in data-independent acquisition (DIA) mode, and simultaneously acquiring a mass spectrometry dataset containing a full-scan fingerprint of the parent ion and fragment information of the daughter ion by alternating between low and high collision energies; extracting the precise mass number of PCA from the dataset for accurate quantification, and calculating the PCA content using the difference method; simultaneously retrieving the total ion chromatogram and inferring the source of PCA based on the response of other amino acids. This invention is the first to introduce microwave digestion pretreatment and high-resolution mass spectrometry DIA acquisition mode into the field of PCA detection in fertilizers, requiring only a single injection to simultaneously complete accurate quantification and source identification, effectively avoiding false positives caused by background of plant and animal protein hydrolysates, and significantly improving the efficiency and confidence of PCA detection in complex matrix fertilizers.

The invention relates to the technical field of mass spectrum detection, particularly discloses a mass spectrum ionization source for detecting volatile substances in combination with radio frequency discharge, and solves the problems of tedious sample pretreatment steps, long analysis period, high instrument cost and the like when a traditional ion source is used for analyzing the volatile substances in the existing mass spectrum technology. The ionization source is used for ionizing molecules of a sample to be detected; the mass spectrometric detection method of the ionization source comprises the steps that stable low-temperature plasma is generated under the atmospheric pressure condition through radio frequency discharge, the low-temperature plasma directly interacts with an introduced to-be-detected sample, volatile substance molecules in the to-be-detected sample are efficiently ionized, and then generated ions are introduced into a mass spectrometer for analysis. The device has the advantages of being simple in structure, convenient to operate, free of complex sample pretreatment, high in analysis speed and the like, and an efficient and economical new way is provided for rapid and direct detection of volatile substances.

The invention relates to the technical field of tobacco chemical analysis, in particular to a multistage mass spectrometry identification method for chemical structures of sucrose esters in tobacco and tobacco products, which comprises the following steps: crushing and extracting a tobacco product sample; carrying out solid-liquid separation and filtration to obtain a liquid to be detected; separating the liquid to be detected by adopting hydrophilic interaction chromatography; performing triple quadrupole-ion trap tandem mass spectrometry analysis on the components separated in the step S2 by adopting an electrospray ion source in a positive ion mode to sequentially obtain mass spectrometry information of parent ions, daughter ions and grandchild ions; and determining the chemical structure of the sucrose ester based on the mass spectrum information of the parent ion, the daughter ion and the grandchild ion measured in the step S3. According to the method, complex pretreatment steps are not needed, sucrose esters with different configurations can be identified more efficiently, interference can be effectively eliminated, and substituent group structure information of a low-content target object can be scientifically confirmed.

The invention discloses a molecular ion reaction chamber for chemical ionization mass spectrometry, which comprises a sampling module, a gas inlet module, a reaction module and a power supply module, and is characterized in that the sampling module is provided with a main pipeline and a drainage bypass; the center of the air inlet module is provided with a hole for fixing the capillary; an ion source air inlet channel is arranged close to the side surface of the top end of the reaction module, and an air outlet hole is formed in the center of the bottom surface of the reaction module; sampling gas enters from the top end of the conical cavity from the main pipeline through the capillary tube and reacts with ions entering from the ion source gas inlet channel in the conical cavity, and the reacted gas enters the mass spectrum detector from the gas outlet hole; the power supply module provides a radial focusing electric field for the conical cavity. The drainage bypass effectively reduces the response time of the reaction cavity to organic matters, the capillary tube can be replaced according to different experimental conditions, the conical reaction cavity structure effectively reduces ion loss and improves the ionization efficiency in a laminar flow state, and the molecular ion reaction process is effectively controlled through an external temperature adjusting device and a vacuum pump.

A method of mass spectrometry comprises applying voltages to a mass filter such that it simultaneously transmits precursor ions, 15 & 13, within multiple separate mass transmission windows, 12 & 14, to an ion separator device, such as an ion mobility separator (IMS), while filtering out, or attenuating and transmitting, other precursor ion species. The simultaneously transmitted precursor ions are then separated in, for example, the IMS device so as to provide different ones of the precursor ion species to a fragmentation or reaction device at different times, said ions being sequentially fragmented or reacted so as to form fragment or product ions. The fragment or product ions are then detected in a mass analyser and associated with their respective precursors based on their times of detection therein.

The invention discloses a liquid chromatography-mass spectrometry-based metabolite detection method, which comprises the following steps of: firstly, obtaining information such as retention time, parent ions and daughter ions of a metabolite standard substance by using ultra-high performance liquid chromatography-high resolution mass spectrometry; and then monitoring the intensity of metabolite ion pairs in a specific retention time window by using a multi-reaction monitoring mode (schemed MRM) of ultra-high performance liquid chromatography-triple quadrupole mass spectrometry, optimizing mass spectrum parameters, and finally establishing a metabolite database with high coverage and high sensitivity. The relative abundance of various metabolites such as amino acid, nucleotide and sugar in animal and plant tissues and cells can be measured by utilizing the database. According to the invention, the high-resolution mass spectrum and the triple quadrupole mass spectrum are combined, so that the rapid establishment of the low-concentration metabolite high-throughput detection method is realized.

The invention discloses a novel high-sensitivity and high-flux carbohydrate compound recognition method based on chlorine enhanced ionization. The method comprises the following steps: extracting carbohydrates in a to-be-detected sample to obtain a carbohydrate extracting solution; chloromethyl triphenylphosphonium chloride is optimally selected from 23 quaternary phosphonium salts, quaternary ammonium salts and inorganic ammonium salts as a chlorine affinity reagent added to a mobile phase, and a carbohydrate extracting solution is subjected to targeted and non-targeted scanning analysis by liquid chromatography-tandem high-resolution mass spectrometry (UPLC-ESI-HRMS); and identifying unknown carbohydrate compounds and analyzing the content of known carbohydrates by utilizing a high-resolution mass spectrum scanning result. According to the method, the chloromethyl triphenylphosphonium chloride chloroaffinity reagent is added into the mobile phase, so that the detection sensitivity and the separation effect of the carbohydrates are remarkably improved, and the carbohydrates are analyzed with small sample amount, low interference and high sensitivity; meanwhile, the chlorine isotope labeled carbohydrates have the isotope distribution characteristic, and polysaccharide can generate double-charge molecular ion peaks, so that the mass spectrum detection mass range is remarkably increased, a new technology is provided for screening the high-quality coverage range of the carbohydrates in food, biological and environmental samples, and the method has originality.

The application belongs to the technical field of analytical chemistry, and discloses a qualitative analysis method of ethinyl estradiol and degradation products thereof, which comprises the following steps: determining an accurate mass database and a mass spectrum library of the ethinyl estradiol and degradation products thereof to be detected by using an ultra-high pressure liquid chromatography-quadrupole-electrical field orbitrap high resolution mass spectrometer; detecting the sample by using the ultra-high pressure liquid chromatography-quadrupole-electrical field orbitrap high resolution mass spectrometer; and comparing and analyzing the detection result of the sample with the established accurate mass database and mass spectrum library, so that when the detection result matches the information of the accurate mass database and mass spectrum library, it is determined that the ethinyl estradiol and degradation products thereof to be detected are detected in the sample. The application can realize high-precision qualitative analysis of the sample to be detected by searching for parent ions and daughter ions of the ethinyl estradiol and degradation products thereof by using the ultra-high pressure liquid chromatography-quadrupole-electrical field orbitrap high resolution mass spectrometer, and establishing a high-resolution database.

The invention discloses a method and a device for performing energy resolution cascade mass spectrometry on a sample based on an ion trap, and the method comprises the following steps: performing ionization treatment on a to-be-detected sample to obtain to-be-detected ions; enabling the to-be-detected ions to enter a linear ion trap, and screening out target ions; amplitude scanning processing is carried out on the target ions, and the amplitude scanning processing comprises the steps that first alternating voltage is applied to the x direction of the linear ion trap so that the target ions can be cracked into daughter ions, and meanwhile second alternating voltage is applied to the y direction of the linear ion trap so that the daughter ions can be separated from the linear ion trap; enabling a detector to obtain the daughter ions so as to obtain a detection result of the to-be-detected sample. According to the method disclosed by the invention, continuous energy scanning and fragmentation of parent ions can be realized through the first alternating-current voltage amplitude which is increased along with time by utilizing a single ion trap and only through single sample introduction, and daughter ions are synchronously emitted by utilizing the constant second alternating-current voltage amplitude in the orthogonal direction for detection; and the efficiency and the accuracy of energy resolution cascade mass spectrometry are improved.

An ion source includes: an atomizer configured to continuously introduce a liquid sample and atomize the liquid sample; a heating and mixing chamber configured to vaporize the atomized liquid sample; and a charge supply unit configured to ionize the vaporized liquid sample. The charge supply unit has a positive pressure with respect to the heating and mixing chamber. The vaporized liquid sample and a gaseous seed ion supplied from the charge supply unit are mixed in the heating and mixing chamber. An auxiliary gas for adjusting a gas flow rate in the heating and mixing chamber can be introduced into the heating and mixing chamber. The heating and mixing chamber has a chamber outlet configured to introduce the ionized liquid sample into a mass spectrometer. The chamber outlet is connected to a first pore of the mass spectrometer.

To provide: a surface treatment agent which enables formation of a surface layer excellent in lubricity; a coating liquid; an article; and an article manufacturing method.SOLUTION: A surface treatment agent comprises a fluorine-containing ether compound having a fluoropolyether chain(s) and a reactive group(s), and satisfies the following requirement 1. Requirement 1: in a mass spectrum showing a relationship between mass / charge ratios of product ions and area intensities, the mass spectrum being acquired from product ions using a second mass spectrometer, IB / IA, which is a ratio of IB, a total of area intensities of peaks corresponding, respectively, to product ions having mass / charge ratios 66 u, 166 u, 182 u and 282 u, to IA, a total of area intensities of peaks corresponding, respectively, to product ions having mass charge ratios of 116 u and 232 u, is 0.025 or more, where the product ions are generated by generating negative secondary ions by irradiating a surface layer, formed on a base material using the surface treatment agent, with pulsed primary ions, separating the generated negative secondary ions on the basis of a mass / charge ratio using a first time-of-flight mass spectrometer, selecting the negative secondary ions having a mass charge ratio of 348 u as precursor ions from the separated negative secondary ions using an ion selection device, and introducing the selected precursor ions into a collision cell and cleaving the precursor ions by high energy collision-induced dissociation.SELECTED DRAWING: None

The present invention provides a method for simultaneously determining low-content active chemical components in Fangji Huangqi Decoction, belonging to the technical field of traditional Chinese medicine component analysis, and comprising the following steps: after decocting the raw materials of Fangji Huangqi Decoction with water, ultrasonic extraction is carried out by using a methanol solution to obtain a test solution, and then the UHPLC-MS / MS method is adopted to precisely absorb the mixed reference solution and the test solution and inject them into an analytical instrument for determination. Compared with the traditional ultraviolet detector, the mass spectrometry can accurately give the mass number information of the precursor ion and the product ion of the analyte while accurately determining the component content, and different from the retention time, the mass number information is more stable, reliable and highly specific as the basis for qualitative identification.

This invention relates to the field of compound analysis and detection, and more specifically to a method for detecting NMP in soil. The method includes sample pretreatment, extraction, purification, concentration, and LC-MS / MS detection: soil samples are purified, coarsely separated using a quartering method, freeze-dried for dehydration, ground, sieved, and homogenized; extracted with deionized water, the supernatant is collected by low-speed shaking and high-speed centrifugation; purified using an HLB solid-phase extraction column activated with methanol and water, concentrated and diluted to volume with nitrogen blowing before detection. Chromatography uses a C18 column with a trapping column, eluted with formic acid-water and formic acid-acetonitrile gradients; mass spectrometry uses electrospray ionization in positive ion mode with multiple reaction monitoring, using a precursor ion of 100, a quantitative product ion of 58.1, and a qualitative product ion of 69.1 for qualitative and quantitative analysis. This method avoids target analyte loss, reduces matrix interference and background contamination, has high sensitivity, accurate qualitative analysis, and stable recovery rate (98.9% spiked recovery), filling the gap in domestic methods for the dedicated detection of NMP in soil, and is suitable for site investigations and environmental monitoring.

A data acquisition method and ion mobility spectrometry-mass spectrometer (100) capable of effectively adapting to DDA or DIA, the data acquisition method comprising a pre-acquisition step (S1), a parent ion selection step (S2) and a daughter ion acquisition step (S3), the pre-acquisition step (S1) obtaining an ion mobility spectrometry-mass spectrometry two-dimensional heat map, the daughter ion selection step (S2) obtaining a daughter ion two-dimensional heat map, and the daughter ion acquisition step (S3) obtaining a daughter ion two-dimensional heat map; in the parent ion selection step (S2), the ion mobility analyzer (2) is configured to be in a filtering mode, parent ions are selected according to the ion mobility spectrum-mass spectrum two-dimensional heat map, and the mobility selection range of the ion mobility analyzer (2) and the mass selection range of the quadrupole mass filter (3) are correspondingly set. The data acquisition method solves the problems that an existing data acquisition method is limited in dynamic range and low in scanning efficiency.

A precursor ion transmission window is moved in overlapping steps across a precursor ion mass range. The precursor ions transmitted at each overlapping step by the mass filter are fragmented or transmitted. Intensities or counts are detected for each of the one or more resulting product ions or precursor ions for each overlapping window that form mass spectrum data for each overlapping window. Each unique product ion detected is encoded in real-time during data acquisition. This encoding includes sums of counts or intensities of each unique ion detected the overlapping windows and positions of the windows associated with each sum. The encoding for each unique ion is stored in a memory device rather than the mass spectral data. A deblurring algorithm or numerical method is used to determine a precursor ion of each unique ion from the encoded data.

The invention discloses a method for detecting a triglyceride double-bond structure isomer. The method comprises the following steps: on the basis of molecular ion peaks [M + N] < + >, fragment ions [M + N-R] < + > and fragment ions [M + N-2R] < + > in a primary mass spectrum result and a secondary mass spectrum result of a triglyceride sample, comparing with a lipid compound database so as to obtain the structure type of each branch chain of the triglyceride sample and determine the mass-to-charge ratio range of the fragment ions [M + N-R] < + >; based on the abundance of acyl chain fragment ions between a molecular ion peak [M + N] < + > and a fragment ion [M + N-R] < + >, the ratio of the abundance and the difference value of the mass-to-charge ratio of the adjacent characteristic acyl chain fragment ions, the positions and cis-trans structures of all branched chain double bonds are determined. According to the method, the fine fragmentation law of the TAG double-bond isomer is disclosed, and a comprehensive TAG double-bond isomer characterization strategy is constructed.

A charge detection mass spectrometer (CDMS) comprises an electrostatic sector field ion trap 40, an inductive image charge detector 400 and a fragmentation device. The electrostatic sector field ion t

A system may control a mass spectrometer to acquire, during a plurality of acquisitions constituting an acquisition cycle, a set of mass spectra of product ions derived from precursor ions isolated based on a parallel isolation window successively positioned throughout a precursor mass-to-charge ratio (m / z) range. The precursor m / z range is divided into a plurality of isolation window units. The parallel isolation window includes, for each acquisition of the acquisition cycle, a set of isolation sub-windows corresponding to a distinct set of isolation window units of the precursor m / z range. At least two adjacent isolation sub-windows of the parallel isolation window are non-contiguous. Each isolation window unit of the precursor m / z range is analyzed at least twice during the acquisition cycle. A mass spectrum for the precursor m / z range may be generated based on the set of mass spectra acquired during the acquisition cycle.

The invention discloses a detection method of a monacolin compound. According to the application, a non-targeted screening thought is adopted, four key daughter ions of the monacolin compound are found for the first time, and non-targeted screening methods of the monacolin compound based on key daughter ion detection are respectively established in a high-resolution mass spectrum and a triple quadrupole mass spectrum by utilizing the property that the compound is easy to crack in a source in a mass spectrum; the distribution and the content of the monacolin compound can be exclusively presented. Compared with a basic analysis method of original substances, the method has the advantages that secondary mass spectrum analysis is not needed, the retention time of the compounds can be quickly locked, and the monacolin compounds are subjected to non-targeted screening; compared with the original analysis method of the monacolin compound, the method can filter out a large part of interference of other compounds, and specifically shows the distribution and content of the monacolin compound. The method can be applied to fermentation products of monascus, aspergillus terreus and other monacolin compound producing strains and products of the fermentation products to detect distribution and relative content of the monacolin compounds, and can also be applied to quality control methods such as establishment of monacolin compound fingerprints, content determination and the like in the matrix.

The invention discloses an in-source cracking controllable pulse direct-current arc induced nano-liter electrospray ionization source and mass spectrum combined system and a detection method. The system comprises a mass spectrum, a quartz capillary tube, a metal coil, a positive wire, a negative wire and a direct-current arc generator. The high charge density characteristic of pulse direct-current arc plasma and the solution polarization effect induced by a metal coil are combined to construct a dual-drive ionization system. Under low voltage, molecular ion integrity is maintained; under high voltage, the characteristic fragment ion strength is obviously enhanced, the compound structure information can be obtained without depending on tandem mass spectrometry, and the problems of time consumption and sample consumption of nanoliter electrospray ionization source analysis are effectively solved. The pulse direct-current arc provides high-density positive and negative charges, the metal coil strengthens directional migration of charged species to the tip of the capillary tube through potential difference, and ionization stability and efficiency are remarkably improved.

The invention discloses an in-vitro unknown drug photoionization mass spectrometry rapid qualitative analysis method, which comprises: S1, dissolving a captured suspected drug sample in an acetone or methanol solution, taking out the supernatant, and transferring into a sample bottle; s2, selecting a polar or non-polar SPME probe to penetrate through the sample bottle isolation pad to be inserted into the sample bottle isolation pad, and extracting; and S3, inserting the probe tube into the sample inlet, pushing the handle rod, extending out of the probe extraction head, and performing thermal desorption to desorb the sample to be detected and enter a mass spectrum ionization area. According to the method, richer ionized ion fragment information and molecular ions are provided in the rapid qualitative analysis and accurate identification process of on-site investigation of drugs and precursor chemicals by using a miniaturized mass spectrum technology, and molecular structure information can be provided for analyzing chemical components of unknown novel drugs by using a compound mass spectrum library.

The invention relates to a method for detecting beta-enorphin, and belongs to the technical field of protein analysis and detection. According to the detection method disclosed by the invention, the beta-enorphin is subjected to liquid mass spectrometry detection through the characteristic peptide fragment of the beta-enorphin. The mass spectrum parent ions and the mass spectrum daughter ions of the characteristic peptide fragment have better specificity, the accuracy of the detection method is improved, the mass spectrum parent ions and the mass spectrum daughter ions of the characteristic peptide fragment have stronger response signals, the signal-to-noise ratio (S / N) of the target peptide fragment is remarkably improved through concentration and purification, and the detection accuracy is improved. The accuracy, repeatability and sensitivity of the method for detecting the beta-enorphin in the sample are better.

An ion spectrometry apparatus for analysing ions from a sample comprising a pre-set target compound. An ambient pressure ionization (API) source ionizes the sample to generate ions. The API source generates the ions periodically during a plurality of successive ion generation time intervals separated by intervening time intervals in which no ions are generated thereby. An ion mobility analysis unit receives ions periodically from the API ion source as generated during successive ion generation time intervals. It transmits ions from amongst the received ions through a drift region between electrodes thereof according to a pre-set combination of a dispersion voltage and a concurrent compensation voltage applied to its electrodes during an ion transmission time interval. Transmission of ions received from the sample is permitted according to ion mobility and the pre-set combination of concurrent values of the dispersion voltage and the compensation voltage is selected to permit transmission of ions from the pre-set target compound and to prevent transmission of other ions amongst said ions from the sample.

A method of treating a particle beam is disclosed, of interest in particular for mass spectrometry for 14C. A particle beam including positive ions is passed through a charge exchange cell containing a target gas. The target gas is electrically insulating at room temperature and pressure. At least some of the positive ions of the particle beam are converted to negative ions by interaction with the target gas. The particle beam incident at the charge exchange cell includes molecules and / or molecular ions which interact with the target gas to reduce the concentration of molecules as a result of repeated collisions with particles of the target gas. A corresponding mass spectrometry system is also disclosed.

The invention discloses a Bailing capsule characteristic ion pair, a characteristic peptide as well as a screening method and application thereof, and the screening method comprises the following steps: carrying out non-targeted data acquisition on a Bailing capsule enzymolysis peptide fragment by adopting an ultra-high performance liquid chromatography-quadrupole rod-time-of-flight mass spectrometry, and extracting candidate ion pairs from the Bailing capsule enzymolysis peptide fragment; detecting in an ultra-high performance liquid chromatography-triple quadrupole mass spectrum by utilizing a multi-reaction monitoring mode, and removing false positive to preliminarily obtain characteristic ion pairs of the Bailing capsule; performing comparative analysis by adopting multiple batches of other fermented cordyceps sinensis powder preparations, and verifying the specificity of the characteristic ion pair of the Bailing capsule; and finally, carrying out structural identification on the peptide fragments corresponding to the characteristic ion pairs, selecting 12 peptide fragments with higher abundance for synthesis, and comparing with molecular ion peaks, retention time and secondary fragments of a synthetic reference substance to confirm 12 characteristic peptide fragments. The method disclosed by the invention is good in repeatability and high in sensitivity, and can quickly and accurately distinguish the Bailing capsules from other similar varieties.