42 results about "Mass chromatogram" patented technology

LC / MS data generated by an LC / MS system is analyzed to determine groupings of ions associated with originating molecules. Ions are grouped initially according to retention time, for example, using retention time or chromatographic peaks in mass chromatograms. After initial groupings are determined based on retention time, ion peak shapes are compared to determine whether ions should be excluded. Ions having peak shapes not matching other ions, or alternatively a reference peak shape, are excluded from the group.

LC / MS data generated by an LC / MS system is analyzed to determine groupings of ions associated with originating molecules. Ions arc grouped initially according to retention time, for example, using retention time or chromatographic peaks in mass chromatograms. After initial groupings are determined based on retention time, ion peak shapes are compared to determine whether ions should be excluded. Ions having peak shapes not matching other ions, or alternatively a reference peak shape, are excluded from the group.

When mass spectrums are formed sequentially by scanning a predetermined mass range repeatedly and a mass chromatogram or the like is created. A predetermined number of arrays of many elements of data arranged on the mass axis and constituting a mass profile within a predetermined mass range are collected on the time axis (S1, S2), target data is corrected for each element of data arrange in the direction of the mass axis by using elements of data adjoining front and rear in the direction of mass axis, and elements of data adjoining front and rear in the direction of time axis, thus performing two-dimensional filtering (S3). Peak number of mass is determined by performing peak detection (S4) on a mass profile formed of the filtered data and then a mass spectrum is formed (S5). Variations in the number of masses of the mass spectrum are thereby suppressed, thus enhancing mass resolution and precision of mass chromatogram.

A method of mass spectrometry. The method starts with gaining a total ion chromatogram by a mass spectrometer. An accumulation mass spectrum indicating vicinities of a desired peak top of the total ion chromatogram is displayed. The operator selects a desired mass peak from the displayed accumulation mass spectrum. Another mass chromatogram that is coincident in elution start time, maximum elution time, and elution end time with the mass chromatogram of the selected mass peak are extracted and selected out as a mass peak. Thus, a mass spectrum of a single component is reconstructed.

High-intensity, spiked noise is reduced in chromatography-mass spectrometry data by applying a nonlinear filter such as a moving median filter to the data. The filter is applied to individual mass chromatograms, plots of ion abundance versus retention time for each detected mass-to-charge ratio, and the filtered chromatograms are combined to form a filtered total ion current chromatogram. Standard linear filters are not effective for reducing noise in liquid chromatography-mass spectrometry (LC-MS) data because they assume a normal distribution of noise. LC-MS noise, however, is not normally distributed.

In quantitation without using the isotope labeling technique, there is no means to detect the presence / absence and the time region of the occurrence of quantitative analysis-inhibitory factors in data for the analysis, and the reliability of the data for the analysis cannot be evaluated. Also, the error of the data due to the occurrence of the quantitative analysis-inhibitory factors cannot be evaluated. In order to solve the problems, first, an internal standard to be detected simultaneously with a component for the analysis is mixed in a mobile phase or an eluate of a liquid chromatograph; under the condition where no quantitative analysis-inhibitory factors occur, a blank sample is analyzed to acquire a mass chromatogram of ions originated from the internal standard; and the result is stored in a data storage unit. Then, a sample for the analysis is mixed to acquire data for the analysis of the sample; and the intensity of ions originated from the internal standard is compared with that of the blank sample in the analysis real time in a data analysis unit. At this time, if an inconsistency exceeding a predetermined threshold is detected, the occurrence of the quantitative analysis-inhibitory factors can be detected. Further, based on the inconsistency, the error range of the data can be given to a data set and the like.

This invention relates to graphical user-interactive displays for use in MS-based analysis of protein impurities, as well as methods and software for generating and using such. One aspect provides a user-interactive display comprising an extracted mass chromatogram (XIC), an MS1 spectrum and an MS2 spectrum, all simultaneously representing a user-selected peptide. Another aspect provides a user interactive display simultaneously presenting paired spectra (XIC, MS1 and / or MS2) for a variant peptide and its corresponding wildtype counterpart.

A data independent acquisition method of mass spectrometry for analysing a sample as it elutes from a chromatography system is disclosed. The method comprises the steps of: ionising the sample to produce precursor ions, selecting a precursor mass range for the sample to be analysed, performing a plurality of MS1 scans and performing at most two sets of MS2 scans. Each of the MS1 scans uses a mass analyser operated at a first, relatively higher resolution, for identification and / or quantitation of the sample in the MS1 domain across the precursor mass range. The set of MS2 scans comprises performing MS2 scans of fragmented mass range segments performed with the mass analyser, operated at a second, relatively lower resolution. In the method, the MS1 scans are interleaved throughout the performing of the set of MS2 scans such that the MS1 scans provide a mass chromatogram of the sample.

In the case where a given mass range is repeatedly scanned to sequentially create mass spectra and create a mass chromatogram or the like, when a number of data, which are arranged on the mass axis and constitute a mass profile of the given mass range, are collected for a predetermined number of the alignment (S1 and S2), a two-dimensional filtering process is performed by correcting the target data, for each data aligned in the mass axis direction, using the data contiguous before and after in the mass axis direction and the data contiguous before and after in the time axis direction (S3). For the mass profile constituted of the data thus processed, a peak detection is performed (S4) and the peak's mass number is determined to create a mass spectrum (S5). Consequently, the mass numbers' fluctuation in the mass spectrum is moderated, the mass resolution is increased, and the accuracy of the mass chromatogram is also increased.

The invention relates to a detection method of a nitrogen-containing compound from a rock extract. The detection method comprises the following steps of (1) pre-treating a rock sample to obtain the rock extract; (2) carrying out family component separation on the rock extract, separating and collecting of nitrogen-containing compound fraction, and concentrating the nitrogen-containing compound fraction to use as a to-be-detected sample; (3) preparing a carbazole standard solution and 9-phenyl-carbazole standard solution, measuring a mass chromatogram by using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry to obtain standard curves of the both; and (4) detecting the to-be-detected sample by using the comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry, qualitatively analyzing the nitrogen-containing compound in the to-be-detected sample according to a retention time and characteristic ions, and quantitatively analyzing the nitrogen-containing compound in the to-be-detected sample. The comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry analysis method of the nitrogen-containing compound in the rock extract overcomes the interference problems of overlapping peaks in conventional GC / MS chromatogram; and the qualitative and quantitative results are accurate and reliable.

A chromatograph mass analysis data processing apparatus is provided for obtaining pertinent information, with a simple operation, on a compound series including a plurality of compounds whose structures and characters are similar. Based on the data obtained by a chromatograph mass analysis, a two-dimensional isointensity line graph is created and displayed with a retention time and a mass-to-charge ratio on the two axes and with a signal intensity represented with a contour (S1). When the operator specifies a desired range by a drag operation or the like through a mouse (S2), the data contained in the range specified are collected (S3), the signal intensities along the mass-to-charge ratio axis direction are summed up for every retention time to create a summed mass chromatogram based on the summed value (S4 and S5). Simultaneously, the signal intensities along the retention time axis direction are summed up for every mass-to-charge ratio to create a summed mass spectrum based on the summed value (S6 and S7). These are then displayed on the same screen of the isointensity line graph (S8).

High-intensity, spiked noise is reduced in chromatography-mass spectrometry data by applying a nonlinear filter such as a moving median filter to the data. The filter is applied to individual mass chromatograms, plots of ion abundance versus retention time for each detected mass-to-charge ratio, and the filtered chromatograms are combined to form a filtered total ion current chromatogram. Standard linear filters are not effective for reducing noise in liquid chromatography-mass spectrometry (LC-MS) data because they assume a normal distribution of noise. LC-MS noise, however, is not normally distributed.

A method and system for detecting pesticide residue in agricultural products. The system includes a chromatographic and mass-spectrometric system and a computer. The system inspects first and second sample solutions prepared from two identical extracts of an agricultural product. The first sample solution includes no additives while the second sample is added with a pesticide standard which is intended to be detected by the system for comparison. The computer compares the mass chromatograms of the first and second sample solutions, and calculate an increased integral area by which the peak of the second sample solution in the second mass chromatogram exceeds the peak of the first sample solution in the first mass chromatogram at the same retention time. As such, the concentration of pesticide residue in the sample can be determined by a ratio between the increased integral area and the concentration of the pesticide standard.

A method of mass spectrometry. The method starts with gaining a total ion chromatogram by a mass spectrometer. An accumulation mass spectrum indicating vicinities of a desired peak top of the total ion chromatogram is displayed. The operator selects a desired mass peak from the displayed accumulation mass spectrum. Another mass chromatogram that is coincident in elution start time, maximum elution time, and elution end time with the mass chromatogram of the selected mass peak are extracted and selected out as a mass peak. Thus, a mass spectrum of a single component is reconstructed.

The invention relates to an analysis method of a gas phase chromatography-flying time mass spectrum of carbazole compounds in crude oil. The method is characterized in that the gas phase chromatography-flying time mass spectrum is adopted to accurately extract the mass chromatograms of carbazole, methyl carbazole, dimethyl carbazole and trimethyl carbazole to overcome the influence of arene and a certain unknown compounds on the carbazole compounds in the prior detection method, thereby having the advantages of accurate qualitation, reliable quantum, data convolution procedure, convenient application, and the like.

The invention relates to an online volatile organic compound detector and method. The online volatile organic compound detector comprises an online preconcentration system, a full two-dimensional gaschromatography device and a controller, wherein the online preconcentration system is connected with the full two-dimensional gas chromatography device, and the two are both connected with the controller; the controller controls the online preconcentration system to capture a to-be-detected sample gas in an online mode, performs corresponding preconcentration and heating analysis processing and send the gas to the full two-dimensional gas chromatography device, completion signals are sent to the controller, and the controller controls the full two-dimensional gas chromatography device to startaccording to the completion signals; and the full two-dimensional gas chromatography device separates the to-be-detected sample gas after detection processing according to preset separation detectionand analysis conditions, and a mass chromatogram is obtained. The full two-dimensional gas chromatography device has the characteristics of high resolution, high sensitivity, fast response, and the like. The obtained mass chromatogram has high reliability. Quantitative and qualitative analysis are carried out according to the mass chromatogram and a preset standard mass chromatogram, and the components of a complex volatile organic compound can be analyzed highly reliably.

The invention provides an automatic interpretation model construction method and device for mass chromatograms and electronic equipment, and the method comprises the steps: obtaining the mass chromatograms corresponding to a plurality of samples, processing each mass chromatogram to obtain corresponding feature data, and calculating to obtain a sample label of each feature data; and training the constructed neural network model by using the feature data carrying the sample labels until a preset requirement is met, thereby obtaining an interpretation model which can be used for performing automatic information analysis on the to-be-processed quality chromatogram. According to the scheme, a machine learning mode is adopted, and the explanation model is obtained through training by obtaining the feature data and the sample labels, so that analysis and explanation of the quality chromatogram data can be automatically realized, and the purposes of extracting more features of the quality chromatogram, reflecting more comprehensive information and realizing high-dimensional analysis can be supported.

A standard mass chromatogram which a substance to be detected exhibits is provided as a database within an apparatus. A measured mass chromatogram obtained by measurement and the standard mass chromatogram stored in the database are compared with each other after their standardization to determine the degree of coincidence of the two. Then, by utilizing the degree of coincidence, it is determined whether the substance to be detected has been detected or not. Further, two ions are selected from among plural ions derived from the substance to be detected and correlation between mass chromatograms of the two selected ions is compared with correlation between mass chromatograms of the two selected ions stored in the database to determine the degree of coincidence of the two. This degree of coincidence is also utilized for determining whether the substance to be detected has been detected or not.

The invention provides a method for quantitatively analyzing four isomers FD-1, FD-2, FD-3 and FD-4 of photocyanine by a liquid chromatography-ion mobility differential mass spectrometry coupling technology. The method comprises the following steps: 1), preparing a photocyanine sample solution; 2), injecting the sample solution into a high performance liquid chromatography-ion mobility differential mass spectrometry serial device to obtain a mass chromatogram; 3), according to the mass chromatogram, quantitatively analyzing the four isomers FD-1, FD-2, FD-3 and FD-4 of the photocyanine by an external standard method, wherein in the high performance liquid chromatography, gradient elution is performed by using a mixed mobile phase consisting of a mobile phase A and a mobile phase B; the mobile phase A is a weakly alkali aqueous mobile phase having the pH value range of 9.5-11.5; the flow phase B is a mixture of methanol and acetonitrile.

A method and system for detecting pesticide residue in agricultural products. The system includes a chromatographic and mass-spectrometric system and a computer. The system inspects first and second sample solutions prepared from two identical extracts of an agricultural product. The first sample solution includes no additives while the second sample is added with a pesticide standard which is intended to be detected by the system for comparison. The computer compares the mass chromatograms of the first and second sample solutions, and calculate an increased integral area by which the peak of the second sample solution in the second mass chromatogram exceeds the peak of the first sample solution in the first mass chromatogram at the same retention time. As such, the concentration of pesticide residue in the sample can be determined by a ratio between the increased integral area and the concentration of the pesticide standard.

The embodiment of the invention provides an organic geochemical recognition method for an effective gas reservoir in tight sandstone. The method comprises the steps that core samples are collected; the core samples are treated, extract saturated hydrocarbon is prepared and collected; a mass chromatogram of the extract saturated hydrocarbon is analyzed, a terpane-series M / Z191 mass chromatogram is extracted and compared with a standard diagram, and peak positions of tricyclic terpane C20, C21 and C23 and corresponding relative peak areas SC20, SC21 and SC23 in the terpane-series M / Z191 mass chromatogram are determined; the core sample with the largest relative peak area of C23 among tricyclic terpane C20, C21 and C23 and the relative peak area specific value SC23 / (SC20+SC21) larger than 1 is used as the effective gas reservoir in the tight sandstone. Through the method, the problem that the effective reservoir in the tight sandstone is hard to recognize during logging can be effectively solved, and the recognition rate of the effective gas reservoir in the tight sandstone is increased.

The invention relates to a method for determining the residual quantity of 10 aminoglycoside antibiotics in eggs, and belongs to the technical field of trace veterinary drug residue detection. The determination method specifically comprises the following steps of: pre-treating a sample, preparing a standard stock solution, a mixed standard intermediate solution and a matrix matching working solution, performing determination by utilizing the matrix matching standard working solution and adopting hydrophilic interaction chromatography-triple quadrupole mass spectrometry, drawing a standard curve, and detecting the to-be-detected solution according to the same instrument parameters, thus obtaining mass chromatograms of the 10 aminoglycosides in the sample, and then carrying out qualitative and quantitative analysis. According to the invention, pollution of ion pair reagents to chromatography and mass spectrometry is avoided, according to the detection method provided by the invention, pollution of heptafluorobutyric acid, sodium heptanesulfonate and other ions to a chromatographic column and a mass spectrometry detector is avoided; the pretreatment operation is simple, the purification effect is good, the sensitivity is higher, the detection limit and the quantitation limit are greatly reduced, and the limit requirement of the national standard on aminoglycoside in eggs is completely met.

A technician is forced to determine the measurement time to be used in a selected ion monitoring (SIM) measurement while observing mass spectral data. Thus, mass spectral data and one or a plurality of mass chromatogram data items is generated on the basis of the detection results of an ion detection unit, and, for each corresponding ion component, the measurement time to be used in SIM is determined on the basis of the elution time range represented by each peak waveform of the one or plurality of mass chromatogram data items that have been generated.

Peaks are detected on a mass chromatogram at multiple m / z ratios characterizing a target component, and the detected peaks are classified into groups according to their occurrence time. The measured mass spectrum is acquired for each group, the measured mass spectrum and standard mass spectrum of the target component are matched for each m / z, and the standard mass spectrum is normalized by multiplying it by the same scale factor for all the m / z ratios such that it does not exceed the peak intensities on the measured mass spectrum. The quantitation ion m / z peak intensity on the normalized standard mass spectrum is then examined, and if this intensity exceeds a preset threshold and the confirmation ion ratio determined based on the measured mass spectrum obtained for the target component is outside a reference range, then that target component is taken as a narrowed result candidate.

The invention provides a method for detecting 9-nitrominocycline in tigecycline for injection. The detection method comprises the following steps: step S1, obtaining a standard curve of high performance liquid chromatography tandem mass spectrometry of 9-nitrominocycline, wherein the vertical coordinate of the standard curve is the characteristic ion peak area of 9-nitrominocycline, and the horizontal coordinate is the mass content of 9-nitrominocycline; step S2, dissolving tigecycline for injection to form a tigecycline solution, and performing high performance liquid chromatography tandem mass spectrometry detection on the tigecycline solution to obtain a mass chromatogram; and step S3, determining the characteristic ion peak of the 9-nitrominocycline in the mass chromatogram according to the analysis result of the mass chromatogram, and calculating the mass content of the 9-nitrominocycline by taking the peak area of the characteristic ion peak as the basis of the standard curve. According to the detection method, the accurate mass content of the 9-nitrominocycline can be obtained and a reliable data basis can be provided for effective mass control of the 9-nitrominocycline.

The invention provides a method for judging ending point of sweet corn blanching, comprising the following concrete steps: 1) after liquid nitrogen quick freezing of sweet corn, carrying out ice-bath homogenization with phosphate buffer with a pH of 7.0 and a proportion of 1: 4 (w / v); 2) taking 8mL homogenate in an extraction bottle, warming up to 60 DEG C, and carrying out headspace solid-phase microextraction for 20 min at the temperature of 60 DEG C; 3) detecting volatile ingredients with gas chromatograph-mass spectrometer method, resolving for 2 min at the temperature of 220 DEG C; 4) integrating a mass chromatogram, retention time alignment and retention index of a standard sample so as to carry out qualitative analysis on hexanal under the conditions of setting a temperature program and separating a chromatographic column strip, and then carrying out qualitative analysis according to a specification curve; and 5) when the content of hexanal in the sweet corn is lower than 4 microgram per gram, determining the ending point of blanching. The test results show that the method has the advantages of being high in rate of accuracy, good in correlation with quality of quick-freeze sweet corn in storage period, and the like.