Method of Processing Spectrometric Data

Abstract

A method of characterising 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 analyses 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 (140). A pattern spectral distance is determined (150) 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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application is a continuation under 35 U.S.C. §120 and claims the priority benefit of co-pending U.S. patent application Ser. No. 12 / 472,262, filed May 26, 2009, which claims the priority benefit of European Patent Application Serial No. 08251890.3, filed May 30, 2008. The disclosures of each of the foregoing applications are incorporated herein by reference.FIELD OF THE INVENTION[0002]This invention relates to a method of processing spectrometric data. The method is preferably though not of necessity implemented in computer software, for analysis of mass spectrometric data.BACKGROUND TO THE INVENTION[0003]Ultra-high resolution mass spectrometry, such as is achievable using a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR-MS), or an Orbitrap™ mass spectrometer, enables the identification of thousands of different molecular formulas in organic matter. Coupled with liquid chromatography (LC), accurate mass d...

AI Technical Summary

Benefits of technology

The present invention relates to a method for improving the accurate assignment of elemental compositions to measured molecular peaks in a sample. This is achieved by scaling the intensity of peaks in the theoretical isotopic spectrum of the candidate composition and / or the measured mass spectrum. By doing so, the accuracy of sample characterization is improved and the time taken to characterize a sample is reduced. The technical effect of the invention is to enhance the accuracy and efficiency of elemental composition analysis.

Problems solved by technology

The output from the mass spectrometer must be interpreted before samples can be characterised, and this presents technical problems.

Molecular formula assignment from mass data is most critical and time-consuming.

Despite technological advances and improved mass accuracy, often the mass accuracy alone does not provide unequivocal identification.

The number of candidate formulae increases exponentially with mass, making high mass molecular determination particularly challenging.

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