Median filter for liquid chromatography-mass spectrometry data
AssigneePPD Biomarker Discovery Sciences, LLC
InventorCurtis Hastings
Life of this patent
Estimating the term…
Abstract
High-intensity, spiked noise is reduced in chromatography-mass spectrometry data by applying a nonlinear filter such as a moving median filter to the data. The filter is applied to individual mass chromatograms, plots of ion abundance versus retention time for each detected mass-to-charge ratio, and the filtered chromatograms are combined to form a filtered total ion current chromatogram. Standard linear filters are not effective for reducing noise in liquid chromatography-mass spectrometry (LC-MS) data because they assume a normal distribution of noise. LC-MS noise, however, is not normally distributed.
Claims20
A method for characterizing a chemical sample, comprising:
- acquiring a series of mass spectra of said sample;
- generating a set of discrete data points based on the mass spectra, said data points comprising a plurality of chromatograms;
- selecting a data filter window size;
- centering said data filter window on one or more particular data points of said set of data points;
- and
- replacing said particular data point with the median of all points within said window to produce a filtered mass chromatogram.
A program storage device accessible by a processor, tangibly embodying a program of instructions executable by said processor to perform method steps for a chemical sample analysis method, said method steps comprising:
- acquiring a series of mass spectra of said sample;
- generating a set of discrete data points based on the mass spectra, said data points comprising a plurality of chromatograms;
- selecting a data filter window size;
- centering said data filter window on one or more particular data points of said set of data points;
- and
- replacing said particular data point with the median of all points within said window to produce a filtered mass chromatogram.
A method of characterizing a chemical sample, comprising:
- obtaining a chromatogram from a series of mass spectra of said sample, wherein said mass spectra are generated by chromatography and mass spectrometry, and wherein said chromatogram comprises signal data and noise data;
- and
- applying a non-linear filter to said chromatogram to remove at least some of said noise data, thereby producing a filtered chromatogram.
Dependencies are inferred from the claim text.