Methods are described for the automatic determination and correction of retention time shift of a MS data set relative to a control data set, to correct for retention time drifts endemic to targeted LCMS analyses. In an embodiment, a 2D grid of periodic MS spectra versus time is collected for a control experiment, and RT windows are determined with an additional set of unscheduled mass spectral analyses. During successive experiments, spectra from periodic MS scans are used to determine the correspondence between the current time and the time in the control experiment. The active set of MSn scans to be acquired by the instrument is then determined as the scans with adjusted retention time windows that bracket the corrected retention time.

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.

For vector A which expresses an absorption spectrum of a target component, vector F orthogonal to vector A is designated as a filter for extracting an impurity superposed on the target component on a chromatogram. For vector I which expresses a measured spectrum obtained by a chromatographic analysis performed on a sample, the inner product of vectors I and F is defined as an index value u of the amount of impurity. If an impurity is present, a peak-like waveform appears on a graph which shows a temporal change in the index value u for the measured spectrum obtained at each point in time of the measurement. By detecting this waveform, the presence or absence of the impurity can be correctly determined. The direction of vector F may be determined so that, when vector B which expresses a spectrum of the impurity is decomposed into vector Ba parallel to vector A and vector Bo orthogonal to vector A, vector F becomes nearly parallel to vector Bo (i.e. the cosine similarity index is maximized).

A chromatographic data processing device, data processing method, and chromatographic analysis system. When chromatographic analysis is performed, the data processing device obtains 3D data for time, wavelength, and strength from the PDA, and finds the assay value for the target component in the liquid sample by processing said data. If the peak top strength of the target component falls outside of the dynamic range, a dilution ratio for the liquid sample is determined by calculating the peak top strength of the target component using the ratio of the strength at the peak top wavelength on the spectrum for each point in time belonging to the peak to the strength of a separate wavelength.

A chromatograph mass spectrometer including: an MS.sup.n-1 analysis setter for setting an analysis execution period for performing an MS.sup.n-1 analysis, an execution time for the analysis and a loop time; an analysis period divider for dividing the analysis period into segments according to a change in number or analysis condition of MS.sup.n-1 analyses to be performed within the same time window; an MS.sup.n analysis setter for performing MS.sup.n-1 analysis to obtain mass spectrum data and for scheduling MS.sup.n analysis, an ion corresponding to a peak satisfying a set condition being designated as a precursor ion; an MS.sup.n analysis execution time allotter for allotting, in each segment, a time period for execution of the MS.sup.n analysis, the time period being calculated by subtracting an event execution time from the loop time; and an analysis executer for repeatedly performing MS.sup.n-1 analysis and MS.sup.n analysis in each segment.

Analysis of chemically samples using gas chromatography (GC) separation with vacuum ultra-violet spectroscopy detection is described. One technique focuses on assigning a specific analysis methodology to each constituent in a sample. Constituents can elute from the GC by themselves or with other constituents, in which case a deconvolution is done using VUV spectroscopic data. In an exemplary embodiment, each constituent may be specifically included in an analysis method during a setup procedure, after which the same series of analyses are done on subsequent sample runs. The second approach essentially integrates an entire chromatogram by first reducing it into a series of analysis windows, or time slices, that are analyzed automatically. The analysis at each time slice determines the molecular constituents that are present as well as their contributions to the total response. Either approach can be used to quantify specific analytes or to do bulk classification.

A chromatograph mass spectrometer for performing SIM measurement and/or MRM measurement on a plurality of target components includes: a memory 41 for previously storing measurement conditions created for each of the target components, the measurement conditions including an SIM measurement ion or an MRM transition, a measurement execution time period, and an initial dwell time; a measurement time divider 42 for dividing an entire measurement time into a plurality of partial time periods having different combinations of measurements executed in the same time period; a time period input receiver 43 for receiving an input for selecting one of the partial time periods; a sensitivity information input receiver 45 for receiving an input of sensitivity information relating to the measurement conditions executed in the selected partial time period; a dwell time calculator 47 for calculating a changed dwell time by increasing or reducing the initial dwell time according to details of the input of the sensitivity information; and a loop time calculator 48 for calculating a loop time from the changed dwell time and outputting the calculated loop time.

Analytical methods that can be employed to reliably separate known or suspected allergens in a complex mixture of fragrance ingredients are described.

Disclosed are methods for improving compound detection and characterization. Methods for characterizing a sample are disclosed. The methods can include providing a sample to a liquid chromatography system capable of sample separation to generate sample components; analyzing sample components by multiplexed targeted selected ion monitoring (SIM) to generate an inclusion list; and performing iterative mass spectral data-dependent acquisition (DDA) from the inclusion list, to identify individual sample components thereby characterizing the sample. In one example, multiplexed targeted SIMs and iterative MS2 DDA acquisition is used to increase robust compound identification for cell culture medium analysis.

A spectral data processing apparatus where a particular spectrum is displayed on a display based on 3D spectral data having time, signal intensities, and a prescribed parameter, comprising: a 2D spectrum calculating unit compiling the signal intensities for each point in time and calculating 2D spectrum of the signal intensities and the prescribed parameter, based on the spectral data; a signal-intensity-time change calculating unit calculating change in signal intensity over time for each value of the prescribed parameter, based on the spectral data; and a display controlling unit displaying, on the display, the 2D spectrum and the change in the signal intensity over time in superimposed manner using multicolor, light and shading, or change in brightness, so that the change in signal intensity over time is displayed to match the prescribed parameter of the 2D spectrum and the time changes along the axis of signal intensities of the 2D spectrum.