65 results about "Daughter Ion" patented technology

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 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 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.

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.

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.

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

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 application provides an animal brain metabolite identification method based on mass spectrometry imaging technology and application, and establishes a mouse brain tissue slice endogenous metabolite DESI-MSI analysis method based on mass spectrometry imaging technology, which comprises the following steps: after preparing metabolite control sample imaging samples and brain tissue slice imaging samples, multiple animal brain tissues are attached to the same glass slide, mass spectrometry imaging condition optimization is carried out by using the control sample imaging samples, and mass spectrometry imaging analysis is carried out by using the brain tissue slice imaging samples; the image of the biological sample is divided into multiple structure regions in combination with tissue morphological characteristics; for the structure regions, multivariate statistical analysis is carried out to obtain different metabolites in different structure regions; metabolite identification is carried out based on parent ions and characteristic daughter ion profiles; and the method is used for disease mechanism research and drug intervention effect evaluation on diseases.

The invention discloses a desorption electrospray and secondary photoionization mass spectrometry imaging device combined with an ion funnel, which comprises a double-light-source secondary ionization component, a two-stage ion funnel, a desorption electrospray ionization source and a three-degree-of-freedom displacement imaging platform for carrying a glass slide of a measured object, the desorption electrospray ionization source is arranged above the three-degree-of-freedom displacement imaging platform and located on one side of the glass slide, an electrospray sampling pipe for sampling molecule-ion droplet clusters is arranged at an inlet of the double-light-source secondary ionization assembly, and the electrospray sampling pipe is arranged above the three-degree-of-freedom displacement imaging platform and located on the other side of the glass slide; an outlet of the double-light-source secondary ionization assembly is connected with an inlet of the two-stage ion funnel, and an outlet of the two-stage ion funnel is externally connected with mass spectrometry equipment. Through the integrated design of double-light-source same-cavity secondary ionization, gas phase doping and the two-stage ion funnel, the ionization efficiency and the ion transmission efficiency of the to-be-analyzed object can be remarkably improved.

The invention discloses a thermal mass spectrometry-based metal precursor pyrolysis characteristic detection method, relates to the technical field of precursor pyrolysis characteristic detection, and aims to solve the problem that the comprehensive purity and impurity content of a product cannot be comprehensively evaluated by a current metal precursor characterization method. A metal precursor is promoted to volatilize in a constant-temperature or temperature-rising heating mode under the protection of inert gas, a thermal weight loss curve is drawn according to the correlation between residual weight and time and temperature, meanwhile, along with decomposition of substances, the weight loss curve jumps, different types of molecular ion fragments can be detected through the combined mass spectrum, and qualitative analysis is achieved. The volatilization rate and the decomposition characteristic of the precursor are represented through a curve and a molecular ion peak, volatilization and decomposition products are quantified through the thermal weight loss proportion and the acquisition proportion of molecular ion fragments, and finally, non-volatile evaporation residues remaining are used as the non-volatile matter impurity content of ultra-pure chemicals. Qualitative and quantitative detection of the purity, impurity components and decomposition characteristics of the metal precursor is realized.

Disclosed is a method, and a system that executes such a method, for elucidation of molecular structures from raw liquid chromatography tandem mass spectrometry (LC-MS / MS) data. The method involves obtaining mass spectrum data, comprising MS1 and MS2 data, from the raw LC-MS / MS data. Compound peaks are then detected by denoising and deconvoluting individual compound fingerprints from the MS1 data. A type of charged adduct corresponding to each precursor molecular ion represented in the MS1 data is determined, and MS1 intensities of an isotope distribution signature for each charged adduct are then obtained. MS2 spectra can subsequently be extracted for each compound corresponding to a compound peak, based on each detected compound peak, charged adduct and MS1 intensities. From this information, a molecular structure can be elucidated from the MS2 spectra by comparing the MS2 spectra to a reference library of reference MS2 spectra and corresponding molecular structures.

This application relates to the field of mass spectrometry analysis technology, specifically a method for the multidimensional fine structure identification of lipids based on the full derivatization of carbon-carbon double bonds. The method includes: in-situ epoxidation derivatization of unsaturated lipids to obtain epoxidation products; mass spectrometry analysis of the sodium ion adduct of the unsaturated lipid / epoxidation product to determine the total number of carbon atoms and the degree of unsaturation of the unsaturated lipid; secondary mass spectrometry analysis of the sodium ion adduct of the epoxidation product to obtain daughter ions after neutral loss of the head group; tertiary mass spectrometry analysis of the daughter ions to obtain specific ions at the sn position and carbon-carbon double bond positions; and analysis of the specific ions at the sn position and carbon-carbon double bond positions to determine the sn position and carbon-carbon double bond position of the unsaturated lipid based on the total number of carbon atoms and the degree of unsaturation. This method can simultaneously resolve the sn-linked positions and carbon-carbon double bond positions of fatty acid chains in unsaturated lipids, achieving multidimensional fine structure identification of lipids.

The invention provides a method for detecting active ingredients of yeast based on a marker polypeptide and application of the method, and belongs to the technical field of biological detection. The method comprises the following steps: preparing characteristic polypeptide standard solutions with different concentrations; preparing a to-be-detected sample solution; an optimized liquid chromatography-mass spectrometry (LC-MS / MS) condition is adopted for qualitative and quantitative analysis, and ion pairs of parent ions m / z 569.39 and daughter ions m / z 438.14 are specifically monitored. The enzymolysis pretreatment conditions including protease selection, enzymolysis temperature, pH value, time and enzyme substrate proportion are further optimized. The method has the advantages of strong specificity, high sensitivity, good stability and the like, and is suitable for yeast peptide raw material purity detection, production process monitoring and quality control of active components of a final product.

The application discloses a kind of carbon positive ion mass spectrometer device based on C + Ion is carried out 14 C analysis method belongs to the technical field of nuclide analysis.The method comprises the following steps: eliminating C-H molecular ion interference by stripping target using specific gas through the way of sectional stripping and charge exchange, then forming C ‑ Ion by charge exchange target of non-metal gas, cooperating with pre-focusing, post-focusing and magnet analysis, to obtain high-intensity C ‑ Ion current intensity;C + Ion current intensity reaches 6-7 mA, C ‑ Ion current intensity after charge exchange reaches 260 μA; the specific gas is any one or more of He gas, Ar gas and N2 gas, and the non-metal gas is any one or more of H2, CH4, C2H4 and C4H 10 . In the application, the C + Ion current intensity generated by ion source is several times higher than that of C 2+ , and the efficiency of generating C + by charge exchange using C 2+ and C ‑ is close, so the efficiency of C + analysis based on C 14 can be several times higher than that of using C 2+ .

The invention discloses a mass spectrometric analysis method for synchronous screening of antibiotics and conversion products in water, and relates to the technical field of environmental analytical chemistry, and the mass spectrometric analysis method comprises the following steps: acquiring and processing a sample to obtain a separated chromatographic fraction and generate initial mass spectrometric data; and executing full-scanning and data-dependent mass spectrum acquisition to obtain a three-dimensional mass spectrum data set. And performing feature matching based on a preset database to generate a candidate compound list. And performing dynamic time alignment correction by using the correlation between the candidate compound retention time deviation and the internal standard substance retention time. And carrying out similarity scoring on the experimental sub-ion spectrogram and the theoretical sub-ion spectrogram. And performing score assignment sorting and false positive filtering in combination with the correction result and the spectrogram score to generate a final identification result. And calculating the quantitative concentration according to the mass spectrum response intensity. According to the method, through dynamic correction of retention time and multi-dimensional assignment verification, the accuracy and reliability of compound identification in a complex water body matrix are improved.

This invention discloses a method for determining polyamines in breast milk and dairy products by gas chromatography-tandem mass spectrometry (GC-MS / MS), comprising: taking 20–200 μL of breast milk or dairy products, adding an isotope mixed standard solution, mixing well, then adding lysis buffer, vortexing thoroughly, centrifuging, taking the supernatant, centrifuging to concentrate and drying, resuspending the dried sample in a mixture of ethyl acetate and trifluoroacetic anhydride, then derivatizing in a water bath at 40–80 °C for 0.5–3 hours, continuing centrifugation to concentrate and dry after derivatization, redissolving in dichloromethane, performing solid-phase extraction purification, blowing the purified solution to near dryness with nitrogen, adding 20–200 μL of a mixture of isopropanol and ethyl acetate to redissolve, and performing GC-MS / MS detection; qualitatively identifying the polyamines based on the qualitative ion pairs and retention times; substituting the ratio of the peak area of ​​the quantitative ion of the polyamine to the peak area of ​​the quantitative ion of the deuterated isotope internal standard into the matrix-matched internal standard curve of the polyamine to obtain the concentration of the polyamine.

The application relates to the technical field of pharmaceutical analysis, and particularly discloses a method for detecting genotoxic impurities in moxifloxacin hydrochloride raw materials or preparations. The method is detected by high performance liquid chromatography-mass spectrometry, liquid chromatography conditions are as follows: a C18 chromatographic column is used, a 0.05%-0.2% formic acid aqueous solution is used as a mobile phase A, a 0%-0.2% formic acid acetonitrile solution is used as a mobile phase B, and gradient elution is carried out; the mass spectrometry adopts an ESI ion source, a positive ion detection mode, a parent ion is 431.15 m / z, a daughter ion is 401.18 m / z, and a collision voltage is 10V-25V. The method provided by the application has strong specificity and high sensitivity, the detection limit is 0.625ppm, the blank that the prior art cannot effectively detect N-nitrosomoxifloxacin impurities in moxifloxacin hydrochloride raw materials or preparations is made up, and then the safety risk of moxifloxacin hydrochloride drugs is reduced.

The invention relates to a method for analyzing a sample comprising one or more molecules of interest by a mass spectrometer, comprising ionizing a multitude of molecules and / or fragments thereof comprised within a sample to obtain a multitude of molecule ions (source ions), and performing mass spectrometry (MS) analysis comprising a. analyzing the molecule ions and / or fragments thereof in a MS1 measurement, thereby acquiring ion mass spectral data of at least a fraction of the molecule ions and / or fragments thereof (source ions) comprising their mass to charge ratio (m / z), b. / c. isolating a first fraction and a second of the molecule ions (precursor ions) having a m / z within a first m / z range (mz1; isolation window) and a second m / z range (mz2; isolation window), using a mass filter device, wherein the first m / z range is selected based on the ion mass spectral data acquired in step a. or one or more iterations of step a. and / or e., and wherein the second m / z range (mz2) overlaps with the first m / z range (mz1), d. fragmenting at least a fraction of the molecule ions (precursor ions) isolated in steps b. and c., separately, to obtain a multitude of biomolecule fragment ions from each of the respective fragmented molecule ions (precursor ions), and e. analyzing the multitude of biomolecule fragment ions in one or more MS2 measurement, thereby acquiring ion mass spectral data of the analyzed biomolecule fragment ions.

A mass spectrometer, the mass spectrometer comprising: an ion accumulation device (14) for accumulating and pulsed output ions (8); the invention relates to a time-of-flight mass analyzer, comprising: an ion mirror (2a, 2b) for reflecting ions; ion accelerators (4) arranged and configured to receive ions from the ion accumulation means and pulse the ions into one of the ion mirrors such that when the ions drift in a drift dimension, the ions reflect back and forth between the ion mirrors in a first dimension; a reflector (12a, 12b) for reflecting the ions in the drift dimension; an ion detector (6) for detecting ions; and a control circuit configured to activate the reflectors to pass the ions multiple times along the drift dimension, and then deactivate one of the reflectors to allow ions to pass to the ion detector and be detected, wherein timing of activation and deactivation of the reflector enables only ions within a first range of mass-to-charge ratios to experience the same number of passes in the drift dimension when the ion detector detects the ions; and wherein a control circuit of the mass spectrometer synchronizes the time when the ion pulses exit the ion accumulation device with the time when the ions are pulsed by the ion accelerator such that only ions having a mass-to-charge ratio within the first range are pulsed by the ion accelerator into the one of the ion mirrors.

One embodiment of the acylcarnitine analysis method according to the present application is a method for analyzing C5 acylcarnitine using a tandem mass spectrometer, the acylcarnitine analysis method including: a measurement step of performing MRM measurement based on at least one of MRM parent-daughter ion pairs of m / z 246 > 187, m / z 246 > 57, m / z 246 > 41, and m / z 246 > 29 on a test object; and a processing step of identifying isovalerylcarnitine and pivaloylcarnitine, which is an isomer of isovalerylcarnitine, in the test object, or determining whether pivaloylcarnitine is contained in C5 acylcarnitine in the test object, using a measurement result obtained in the measurement step. Thus, isovalerylcarnitine and pivaloylcarnitine, which have been difficult to identify in the past, can be favorably identified.

The application belongs to the technical field of mass spectrometry instruments, and particularly relates to a device capable of realizing efficient dissociation of hydrated cluster ions in an ionization source, which comprises a sample inlet tube, a vacuum ultraviolet lamp, an ionization source cavity, a repelling electrode, a transmission electrode group and a vacuum pump, the vacuum ultraviolet lamp, the repelling electrode and the transmission electrode group are sequentially arranged in the ionization source cavity, a direct current voltage is applied to the repelling electrode, and a direct current voltage and a radio frequency voltage are applied to the transmission electrode group. In the application, on one hand, the radio frequency electric field is used to heat the ions, and on the other hand, high-energy photoelectrons in the radio frequency electric field can collide with the hydrated cluster ions sufficiently, so that efficient dissociation of the hydrated cluster ions under high pressure is realized. In addition, the introduction of the radio frequency electric field also increases the molecular ion reaction time and further focuses the sample ions in the ionization source, improves the transmission efficiency of the sample ions, and greatly improves the detection sensitivity of the instrument.