Peak width estimation in mass spectra

Patent metadata

Field	Value
Publication number	US-2022013343-A1
Application number	US-202117186650-A
Country	US
Kind code	A1
Filing date	Feb 26, 2021
Priority date	Jul 10, 2020
Publication date	Jan 13, 2022
Grant date	—

Abstract

The disclosure relates to a method for processing a mass spectrum, comprising: (i) providing the mass spectrum which contains a plurality of data pairs, each data pair being representative of a mass value or mass-related value on a mass scale or mass-related scale and an abundance value or abundance-related value associated with the respective mass value or mass-related value, (ii) selecting a plurality of intervals on the mass scale or mass-related scale, each interval containing a multitude of the said data pairs, (iii) for each interval, applying a first mathematical-statistical analysis to the said data pairs contained in the respective interval in order to derive an interval-specific peak width, and (iv) using the said interval-specific peak widths to determine an estimated peak width for each mass value or mass-related value on the mass scale or mass-related scale.

First claim

1 . A method for processing a mass spectrum, comprising:
providing the mass spectrum which contains a plurality of data pairs, each data pair being representative of a mass value or mass-related value on a mass scale or mass-related scale and an abundance value or abundance-related value associated with the respective mass value or mass-related value, selecting a plurality of intervals on the mass scale or mass-related scale, each interval containing a multitude of the said data pairs, for each interval, applying a first mathematical-statistical analysis to the said data pairs contained in the respective interval in order to derive an interval-specific peak width, and using the said interval-specific peak widths to determine an estimated peak width for each mass value or mass-related value on the mass scale or mass-related scale.

2 . The method of claim 1 , wherein the derivation of the interval-specific peak widths includes computing for each interval an interval-specific degree of reliability, and wherein the determination of the estimated peak widths uses the interval-specific peak widths weighted as a function of the respective degrees of reliability.

3 . The method of claim 1 , wherein the estimated peak widths are determined by at least one of interpolating between the interval-specific peak widths, extrapolating from the interval-specific peak widths, fitting a curve to the interval-specific peak widths, and performing a regression analysis to derive a mathematical relation mapping a mass value or mass-related value to an estimated peak width.

4 . The method of claim 3 , wherein the estimated peak widths are determined by linear or spline interpolation.

5 . The method of claim 3 , wherein the estimated peak widths are determined by fitting of a constant, linear, or higher degree polynomial.

6 . The method of claim 1 , wherein the first mathematical-statistical analysis includes computing an autocorrelation of the mass spectrum (i.e., the mass spectrum's correlation with a shifted version of itself) within the respective interval.

7 . The method of claim 6 , wherein the interval-specific peak width is determined as a full width at half maximum (FWHM) by computing the maximum (R max ) and minimum (R min ) of the autocorrelation and finding the position where the autocorrelation crosses a level given by their arithmetic mean, (R max +R min )/2.

8 . The method of claim 6 , wherein the computation of the interval-specific degrees of reliability includes computing for each interval a signal power of the mass spectrum and a total variation of the autocorrelation.

9 . The method of claim 1 , wherein the values on the mass scale or mass-related scale are expressed in atomic mass units or Daltons.

10 . The method of claim 9 , wherein the length of each interval is between 50 and 1000 atomic mass units or Daltons.

11 . The method of claim 6 , wherein the autocorrelation is computed for a lag ranging between 0 and 1 atomic mass units or Daltons on the mass scale or mass-related scale.

12 . The method of claim 1 , wherein—prior to the first mathematical-statistical analysis—the mass spectrum within each interval is resampled to equidistant values on the mass scale or mass-related scale.

13 . The method of claim 12 , wherein a constant spacing between the equidistant mass values or mass-related values is chosen for each interval such that the resampled mass spectrum within the respective interval consists of the same number of data pairs as the original mass spectrum.

14 . The method of claim 12 , wherein a constant spacing between the equidistant mass values or mass-related values is larger than or equal to one thousandth of an atomic mass unit or one milli-Dalton.

15 . The method of claim 1 , wherein the mass spectrum complemented with estimated peak widths is subjected to a second mathematical-statistical analysis.

16 . The method of claim 15 , wherein the second mathematical-statistical analysis is a peak picking algorithm used to differentiate between signal peaks of different analytical interest in the mass spectrum.

17 . The method of claim 1 , wherein providing the mass spectrum comprises aggregating a plurality of individual mass spectra acquired by the same mass spectrometer over a limited period of time.

18 . The method of claim 17 , wherein the plurality of individual mass spectra is acquired from a sample comprising one of tissue, a tissue section, and an extraction from tissue.

19 . The method of claim 17 , wherein the aggregating includes averaging.

20 . A mass spectrometer having an operating system which is adapted and configured to execute a method according to claim 1 .

21 . A method for processing a mass spectrum, comprising:
providing the mass spectrum which contains a plurality of data pairs, each data pair being representative of a mass value or mass-related value on a mass scale or mass-related scale and an abundance value or abundance-related value associated with the respective mass value or mass-related value, selecting a plurality of intervals on the mass scale or mass-related scale, each interval containing a multitude of the said data pairs, for each interval, applying a first mathematical-statistical analysis to the said data pairs contained in the respective interval in order to derive an interval-specific peak width, and using the said interval-specific peak widths to determine an estimated peak width for a plurality of selected mass values or mass-related values on the mass scale or mass-related scale.

Assignees

• Bruker Daltonik Gmbh

Inventors

• Boskamp Tobias

Classifications

• G06F2218/10

  by analysing the shape of a waveform, e.g. extracting parameters relating to peaks · CPC title

• H01J49/40

  Time-of-flight spectrometers (H01J49/36 takes precedence) · CPC title

• H01J49/0036 Primary

  Step by step routines describing the handling of the data generated during a measurement · CPC title

• H01J49/0027

  Methods for using particle spectrometers · CPC title

• H01J49/0009

  Calibration of the apparatus · CPC title