Shimadzu Corporation

Kyoto University

Hiroaki Kozawa

Yuki Ishikawa

Shinji Kanazawa

Shinichi Yamaguchi

Daisuke Okumura

Takeshi Yoshida

Hideki Yamamoto

Akira Noda

Toshinobu Yanagisawa

Tomoyuki Oshiro

Tohru Shiohama

Yuji Katsuyama

Minoru Fujimoto

Yuichiro Fujita

Yuta Miyazaki

Yasushi Ishihama

Atsushige Ikeda

Kazuyoshi Yoshii

A sample chromatogram produced by measurement of a mobile phase into which a sample has been injected is acquired by a sample chromatogram acquirer. A background chromatogram produced by measurement of a mobile phase into which a sample is not injected or a mobile phase into which a control sample is injected is acquired by a background chromatogram acquirer. Alignment of a sample chromatogram and a background chromatogram is performed by an alignment processor by causing of baselines of the acquired sample chromatogram and the acquired background chromatogram to coincide with each other. Subtraction processing of subtracting a background chromatogram from a sample chromatogram after alignment is executed by a subtraction processor.

Waveform processing device for chromatogram and waveform processing method for chromatogram

In order to appropriately set MSanalysis conditions, an MSanalysis executer () makes a mass spectrometer () perform an MSanalysis (where m is an integer from 2 to n) to acquire three-dimensional data showing an intensity for each of the N m/z values and each of the M retention times (where N and M are natural numbers). Based on the three-dimensional data, a data matrix creator () creates data matrix X in which intensity data are arranged in N rows which differ from each other in m/z value and M columns which differ from each other in retention-time value. A matrix factorization executer () determines an N×K spectrum matrix S and K×M profile matrix P (where K is a natural number) by matrix factorization based on data matrix X so that this matrix X is approximated by product SP of the matrices S and P. An m/z detector () detects m/z of a precursor ion originating from a sample component from the values of the matrix elements in each column of matrix S. A retention time detector () detects the retention time of a sample component from the values of the matrix elements in each row of matrix P. Based on the m/z and retention time, an MSanalysis execution condition determiner () determines an execution condition of an MSanalysis including the selection and fragmentation of a precursor ion of a sample component. An MSanalysis executer () makes the mass spectrometer execute an MSanalysis based on the execution condition.

Chromatograph mass spectrometer

A waveform processing assistance device includes an acquirer that acquires a plurality of waveform data obtained by an analysis of a sample, a selector that selects reference data among the waveform data, an extractor that extracts correct answer peaks and correct answer data from the reference data a determiner that determines each processing section including a correct answer peak and each parameter initial value, a waveform processor that performs waveform processing in each determined processing section based on each parameter initial value, an adjuster that generates a parameter adjustment value at which a waveform processing result obtained in each processing section matches or approximates corresponding correct answer data, and a program creator that creates a waveform processing execution program that includes an instruction to execute waveform processing using the parameter adjustment value in each processing section.

Waveform processing assistance device and waveform processing assistance method

A method for detecting a peak in data of a chromatogram or a spectrum, includes: detecting multiple tentative peaks in the data on the basis of a predetermined criterion; determining an actual measurement value of a predetermined feature value indicating a size of a tentative peak from each of the detected multiple tentative peaks, the feature value; determining a smoothed curve on the basis of respective horizontal axis values and actual measurement values of the multiple tentative peaks; determining a reference value of the feature value with respect to each of the multiple tentative peaks from the smoothed curve; and detecting, of the multiple tentative peaks, a tentative peak whose actual measurement value is within a predetermined range from the corresponding reference value as a true peak. Only tentative peaks whose actual measurement value is within a predetermined range from the corresponding reference value as a true peak.

Peak detection method and data processing device

A first reference line that is a regression line obtained from data within a predetermined range including a starting point of a peak detected from data of a graph showing changes in intensity with respect to a parameter, a second reference line that is a regression line obtained from data within a predetermined range including a ending point of the peak, and a third reference line connecting the starting and ending points, and one or more intermediate control points in a triangle defined by the first, second, and third reference lines are determined; and a Bezier curve between the starting point and the ending point is created to be determined to be a baseline of the peak, the Bezier curve being determined by control points of the starting point, the one or more intermediate control points, and the ending point in order on a parameter axis.

Method and device for processing data

A method includes: performing a time-frequency analysis on measurement data to obtain waveform data representing a temporal change in the intensity of each of a plurality of frequency components; dividing the waveform data of each of a plurality of predetermined frequencies into a plurality of segments so that each section where positive values successively occur and each section where negative values successively occur in a time-axis direction are defined as one segment; calculating the area of each of the segments to obtain segment values; creating, for the waveform data of each of the predetermined frequency components, a selected segment group by excluding a segment whose segment value exceeds a predetermined reference value from the segments in the waveform data; and determining a noise level of each of the predetermined frequency components based on the average value of the segment values of the segments included in the selected segment group.

Noise level estimation method, measurement data processing device, and program for processing measurement data

For an automatic adjustment of a detector voltage, a measurement of a standard sample is performed, in which a reflection voltage generator under the control of an autotuning controller applies, to a reflector, voltages which are different from those applied in a normal measurement and do not cause temporal conversion of ions. Ions having the same m/z simultaneously ejected from an ejector are dispersed in the temporal direction and reach a detector. Therefore, a plurality of low peaks corresponding to individual ions are observed on a profile spectrum. A peak-value data acquirer determines a wave-height value of each peak. A wave-height-value list creator creates a list of wave-height values. A detector voltage determiner searches for a detector voltage at which the median of the wave-height values in the wave-height-value list falls within a reference range.

Time-of-flight mass spectrometer

Provided is a mass spectrometric data analyzing method for deducing the structure of an unknown substance from data obtained by an MSanalysis, in which a structural candidate having a high degree of freedom for covering a structural change of the known substance can be created. In the mass spectrometric data analyzing method according to the present invention, a candidate of the partial structure of a known substance which is structurally similar to an unknown substance as the target of deduction is created by eliminating a part of the structure of the known substance (Step S). Previously given candidates of known additional structural parts are individually added to each candidate of the partial structure of the known substance, thus forming various combinations (Step S). All the structural formulae that can be derived from each combination are created as the structural candidates of the unknown substance (Step S).

Method, system and program for analyzing mass spectrometoric data

A peak extraction method for extracting a true peak from a measured waveform, including acquiring a second derivative waveform; extracting a provisional peak on the basis of a maximum value and/or a minimum value of the second derivative waveform; determining the peak width of the provisional peak on the basis of a model peak function; computing, on the basis of the model peak function, a theoretical value for the height of the provisional peak using two points corresponding to the two ends of the peak width; computing, based on the second derivative waveform, an index value for a variation in the noise on the measured waveform; and computing an S/N ratio, which is a ratio of the peak height theoretical value and the index value, and extracting the provisional peak that is equal to or greater than a preset value as the true peak.

Peak extraction method and program

Under the control of an analysis control unit (), a mass spectrometer unit () performs a product-ion scan measurement for a target component in a target sample within a time range where the component is introduced. It also performs a scan measurement over an m/z range including the m/z of an ion originating from a standard component within the same segment of time. A mass correction information calculator () calculates mass correction information from measured and theoretical values of the m/z of the ion originating from the standard component observed on an MS spectrum obtained by the scan measurement. Using the mass correction information, a mass corrector () corrects the m/z of each ion peak originating from the target component observed on an MS/MS spectrum obtained by the product-ion scan measurement performed within the same cycle as the scan measurement concerned. It is possible to consider that the MS measurement and the MS/MS measurement within the same cycle have been almost simultaneously carried out. Accordingly, a mass correction which is almost equivalent to an internal standard method can be achieved.

Tandem mass spectrometer

A device for detecting a peak end point including a peak end point position detecting unit for using, as a base point, a position on horizontal axis at which a local maximum value is obtained to detect, as a position on horizontal axis of a peak end point, a first point at which a value of the inflection point extraction waveform decreases to the relative threshold value in a direction farther from a position on horizontal axis corresponding to the peak top position, and detecting, as the peak end point, a point on the peak detection target waveform corresponding to the position on horizontal axis of the peak end point.

In-waveform peak end point detecting method and detecting device

A waveform data processing devicecapable of accessing a storage devicefor storing data on an observed waveform such as a chromatogram, information on a starting point and an ending point of a peak cluster consisting of a plurality of peaks close one another present on the observed waveform, and information on a position of each peak included in the peak cluster and a positive/negative direction of the each peak, includes baseline determination means for determining, based on the data and the information stored in the storage device, a shortest straight line or shortest line segments from the starting point of the peak cluster as a beginning point to the ending point of the peak cluster as a finishing point satisfying all following conditions, and determining the straight line or the line segments to be a baseline of the peak cluster: (1) in a section where positive peaks are contiguous, a baseline passes below the observed waveform, becoming a straight line or line segments convex downward; (2) in a section where negative peaks are contiguous, a baseline passes above the observed waveform, becoming a straight line or line segments convex upward; and (3) in a section where positive and negative peaks are contiguous, the shape of a baseline is not influenced by the observed waveform.

Waveform data processing device and waveform data processing program

In a method for estimating a noise level representing the magnitude of a noise component from measurement data, first waveform data composed of high frequency noise components extracted from assumed noise data are divided into segments so that each section where positive values successively occur or each section where negative values successively occur in the first waveform data is defined as one segment. A segment-width threshold is determined based on the distribution of the widths of the segments. Second waveform data composed of high frequency noise components extracted from measurement data are divided into segments in the same manner. Each segment having a width larger than the threshold is excluded from the segments in the second waveform data, to create a first segment group. The noise level is determined based on the heights or areas of the plurality of segments included in the first segment group.

Noise level estimation method, measurement data processing device and program for processing measurement data

For a signal waveform to be processed, the continuous wavelet transform is performed with various scale factors, and a wavelet coefficient at each point in time is calculated. On an image showing the strength of the wavelet coefficient with respect to the scale factor and time, ridge lines are detected, and based on these ridge lines, positive and negative peak candidates are extracted, after which an error in the position and width of the peak due to the influence of a neighboring peak is corrected. Subsequently, the degree of non-symmetry of the peak shape or other features are examined to remove false negative peaks due to negative peak artifacts. Subsequently, a true peak cluster, a false peak cluster resulting from the removal of high-frequency components of a high-frequency noise or other causes, and other kinds of peaks are identified, and the obtained result is used to remove false peaks.

Peak detection method

In estimating a structural formula of an unknown substance produced through partial structural change of an original substance having a known structure caused by metabolism or the like, structural change is considered in two stages, the elimination of a partial structure and the addition of another partial structure. First, an additional partial structure is collected as known information in addition to an MSspectrum of the unknown substance and a structural formula of the original substance. A structural formula at the time when a partial structure is eliminated from the original substance is estimated, and a structural formula of each of product ions is estimated. The structural formula of the unknown substance is determined by estimating a structure that can produce the candidates for structural formulas of the product ions by dissociation.

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Kyoto, Japan

Hiroaki Kozawa