Thermo Fisher Scientific (bremen) Gmbh

Thermo Fisher Scientific Gmbh

Hans Pfaff

Robert Malek

Katja Tham

Christoph Henrich

Timothy J Stratton

Martin Strohalm

Evgenia Razumovski

There is provided a method of measuring a mass of an ion species in a mass stream. Where the mass stream is a mass stream emitted from a separation device as a function of a separation parameter, the method comprising: obtaining a mass trace for the ion species, wherein the mass trace comprises a set of intensity peaks, each intensity peak providing a respective measured mass and a respective signal measured by a mass spectrometer; and determining the mass of the ion species as an extrapolation of the measured masses of the set of intensity peaks of the mass trace towards a signal zero.

Systems and methods for determining mass of an ion species

A measure of abundance is determined for an element or element combination within a sample, the element or element combination having at least one isotopic variant. An isotopic mass spectral pattern is identified for the element or element combination that indicates an expected abundance and expected mass-to-charge ratio difference for each isotopic variant. These are identified relative to the respective abundance and mass-to-charge ratio of a principal isotope. The isotopic mass spectral pattern is compared with mass spectral data from a molecular mass analysis of the sample to identify peak groups, each matching the isotopic mass spectral pattern. A measure of abundance is determined for the element or element combination as a function of the intensity measurement of one or more peaks from each of the identified peak groups.

Isotopic pattern recognition

Methods of identification of at least one most likely elemental composition of at least one species of molecules contained in a sample and/or originated from a sample by at least one ionisation process are provided. The method includes measuring a mass spectrum of the sample and may include reducing the measured mass spectrum to a neutral mass spectrum. The method further includes determining for a peak of interest a set of candidate species of molecules which have an expected peak with a peak position within a peak position tolerance range in the corresponding measured mass spectrum or neutral mass spectrum. An identification mass spectrum is identified for each candidate species and a range of peak positions is determined of all peaks of the identification mass spectrum. Two subscores of candidate species are determined by comparing the identification spectra with the measured or neutral mass spectrum and final scores are calculated from the subscores. An elemental composition of the candidate species is determined having calculated final scores of the highest values.

Method for identification of the elemental composition of species of molecules

A computer implemented method for compressing mass spectrometry data, the method comprising decomposing the mass spectrometry data of a mass stream emitted from a separation device as a function of a separation parameter into a plurality of mass traces, wherein the mass spectrometry data are generated by analysis in a mass spectrometer; identifying erroneous mass traces in the plurality of mass traces by applying an event detection algorithm to each of the plurality of mass traces; and forming a compressed version of the mass spectrometry data from the mass traces and the mass spectrometry data corresponding to the identified erroneous mass traces.

Systems and methods for extracting mass traces

A method of extracting a mass trace from mass spectrometry data of a mass stream emitted from a separation device as a function of a separation parameter, the method comprising, receiving the mass spectrometry data, wherein the mass spectrometry data comprise a plurality of mass spectra each obtained for respective values of the separation parameter; identifying, from the plurality of mass spectra, a sequence of three or more intensity peaks that are ordered according to the separation parameter, wherein said identifying the sequence of intensity peaks comprises, selecting an initial intensity peak at an initial mass, and for each other intensity peak, selecting said intensity peak based on at least the mass of an adjacent intensity peak in the sequence of intensity peaks, the method further comprising, providing a mass trace, for a given emitted compound of the mass stream, from the identified sequence of intensity peaks.

A method of and apparatus for improving the resolution of compounds eluted from a separation device are disclosed, particularly suited for use in the fields of gas or liquid chromatography. Embodiments of the invention provide that spectroscopic data are measured from an effluent eluted from a chromatography device as a function of elution time; peaks in intensity are identified to form a first set of identified peaks; peaks not due to an eluting compound are discarded from the first set of identified peaks thereby forming a second set of identified peaks from those retained; each peak in the second set of peaks is transformed into a first model peak centered on the elution time of each peak in the second set of peaks; some or all the model peaks created are added together to create a new chromatogram; and all identified peaks in intensity in the second set of peaks having elution times within a given time period of identified peaks in intensity in the new chromatogram are grouped together and assigned to a single eluted compound thereby forming a processed data set.

Method of improving the resolution of compounds eluted from a chromatography device

A method of characterizing a sample from spectrometric data using calculation of spectral distance values is disclosed, for use in the field of mass spectrometry. Molecular formula assignment of peaks in mass spectral data is difficult and time-consuming, and the invention provides a computer implemented method of finding a most likely elemental composition of a measured spectral peak of interest. The method analyzes isotopic peaks in a portion of the spectrum, using both their mass positions and intensities, to determine a spectral distance between those peaks and isotopic peaks of a candidate composition, finding peaks that match (). A pattern spectral distance is determined () to provide a measure of the correspondence between a set of those peaks in the measured spectrum and peaks of each of a number of candidate compositions. The spectral fit is used to determine a most likely candidate composition.

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Bremen, Germany

Hans Pfaff