Methods for time-alignment of liquid chromatography-mass spectrometry data

• US 7,628,914 B2
• Filed: 01/24/2006
• Issued: 12/08/2009
• Est. Priority Date: 05/09/2002
• Status: Expired due to Fees

• Current Assignee: Caprion Proteomics Inc. (CellCarta Biosciences, Inc.)
• Original Assignee: PPD Biomarker Discovery Sciences LLC (CellCarta Biosciences, Inc.)
• Inventors: Norton, Scott M.
• Primary Examiner(s): Therkorn; Ernest G
• Application Number:
  US11/339,235
• Publication Number:
  US 20060131222A1
• Time in Patent Office: 1,414 Days
• Field of Search: 210/635, 210/656, 210/198.2, 73/615.2, 250/282, 250/288, 702/30
• US Class Current: 210/198.2
• CPC Class Codes: G01N 30/7233 interfaced to liquid or supercritical fluid chromatograph interfaces in general for introducing or extracting samples to be analysed with specially adapted mass spectrometer, see H01J49/04
• CPC Class Codes: G01N 30/8624 Detection of slopes or peaks; baseline correction
• CPC Class Codes: G01N 30/8631 Peaks
• CPC Class Codes: G01N 30/8644 Data segmentation, e.g. time windows
• CPC Class Codes: G01N 30/8668 using retention times
• CPC Class Codes: G06F 2218/12 Classification; Matching
• CPC Class Codes: H01J 49/0036 Step by step routines describing the handling of the data generated during a measurement

Abstract

Nonlinear retention time variations in chromatography-mass spectrometry data sets are adjusted by time-alignment methods, enabling automated comparison of spectra for differential phenotyping and other applications.

Claims

1. A program storage device accessible by a processor, tangibly embodying a program of instructions executable by said processor to perform method steps for a method for time-aligning chromatography-mass spectrometry data sets, each comprising a plurality of mass chromatograms, said method steps comprising:

a) receiving data generated by a mass spectrometer;

b) computing a distance function between said data sets in dependence on at least two mass chromatograms from each data set; and

c) aligning said data sets by minimizing said distance function to obtain aligned data sets.

2. A program storage device accessible by a processor, tangibly embodying a program of instructions executable by said processor to perform method steps for a method for time-aligning two-dimensional chromatography-mass spectrometry data sets, said method steps comprising:

a) receiving data generated by a mass spectrometer;

b) selecting peaks in said data sets;

c) identifying potentially corresponding peaks from said selected peaks; and

d) performing a locally-weighted regression smoothing on said potentially corresponding peaks to obtain aligned data sets.

3. The program storage device of claim 2, wherein the step of selecting of peaks is performed automatically.

4. The program storage device of claim 2, wherein one of said data sets is a reference data set and one of said data sets is a test data set, and wherein said test data set is aligned to said reference data set.

5. The program storage device of claim 2, wherein said data sets are liquid chromatography-mass spectrometry data sets.

6. The program storage device of claim 2, wherein the step of performing said locally-weighted regression smoothing is a robust locally-weighted regression smoothing.

7. The program storage device of claim 6, wherein said robust locally-weighted regression smoothing comprises robust LOESS.

8. The program storage device of claim 2, wherein the said step of performing said locally-weighted regression smoothing is performed in dependence on a span.