Apparatus and method for processing of mass spectrometry data

• US 7,488,935 B2
• Filed: 06/24/2005
• Issued: 02/10/2009
• Est. Priority Date: 06/24/2005
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Altmayer, Lee H.
• Primary Examiner(s): Berman; Jack I
• Assistant Examiner(s): SMYTH, ANDREW P
• Application Number:
  US11/165,871
• Publication Number:
  US 20070023642A1
• Time in Patent Office: 1,327 Days
• Field of Search: 250/288, 250281-300
• US Class Current: 250/281
• CPC Class Codes: G06F 2218/08 Feature extraction
• CPC Class Codes: H01J 49/0036 Step by step routines describing the handling of the data generated during a measurement

Abstract

A mass spectrometry system is described. The mass spectrometry system includes an ion source to ionize a sample stream, a detector positioned downstream with respect to the ion source to acquire mass spectrometry data of the sample stream, and a data analyzer connected to the detector. The data analyzer includes a chromatogram generator to process the mass spectrometry data to derive a chromatogram, a data point selector to apply a selection criterion to the chromatogram to select data points from the chromatogram, and a peak discriminator to apply a discriminating criterion to the data points to detect a peak in the chromatogram, wherein the peak is indicative of a presence of an analyte in the sample stream. A computer-readable medium for a mass spectrometry system and a method of processing mass spectrometry data are also described.

Claims

1. A mass spectrometry system, comprising:

(a) an ion source to ionize a sample stream;

(b) a detector positioned downstream with respect to the ion source to acquire mass spectrometry data of the sample stream; and

(c) a data analyzer connected to the detector and comprising;

(i) a chromatogram generator to process the mass spectrometry data to derive a chromatogram that includes a sequence of data points arranged based on scan number;

(ii) a data point selector to reorder the sequence of data points according to magnitudes of the sequence of data points to thereby generate a reordered sequence of data points and to apply a selection criterion to the reordered sequence of data points to select data points from the chromatogram; and

(iii) a peak discriminator to apply a matched filter to the data points to detect a peak in the chromatogram, wherein a width of the matched filter is defined based on an expected width of the peak, and the peak is indicative of a presence of an analyte in the sample stream.

2. The mass spectrometry system of claim 1, wherein the chromatogram corresponds to one of a total ion chromatogram, a base peak chromatogram, and a mass chromatogram.

3. The mass spectrometry system of claim 1, wherein the data point selector is configured to apply the selection criterion to select the data points based on magnitudes of the data points.

4. The mass spectrometry system of claim 1, wherein the peak discriminator is configured to apply the matched filter to identify a first set of data points from the data points as corresponding to the peak.

5. The mass spectrometry system of claim 4, wherein the peak discriminator is configured to apply the matched filter to identify a second set of data points from the data points as corresponding to a spike.

6. The mass spectrometry system of claim 1, wherein the data analyzer further comprises a peak area calculator to calculate an area of the peak, wherein the area of the peak is indicative of an amount of ions produced from the analyte.

7. The mass spectrometry system of claim 6, wherein the data points correspond to first data points from the chromatogram, and the peak area calculator is configured to apply an analysis to second data points from the chromatogram to derive a baseline.

8. A computer-readable storage medium for a mass spectrometry system, comprising:

(a) code to select data points from a chromatogram based on magnitudes of the data points, wherein the chromatogram comprises a sequence of data points arranged based on scan number, each data point of the sequence of data points has a magnitude that is indicative of abundance for a particular scan number, and the code in (a) comprises;

(i) code to arrange the sequence of data points based on magnitude to derive a reordered sequence; and

(ii) code to select the data points from the reordered sequence of data points; and

(b) code to apply a discriminating criterion to the data points to detect a peak in the chromatogram, wherein the peak is indicative of a presence of an analyte.

9. The computer-readable storage medium of claim 8, wherein the code in (a) comprises code to select the data points from the reordered sequence of data points based on the magnitudes of the data points with respect to a lower threshold value.

10. The computer-readable storage medium of claim 8, wherein the code in (a) comprises code to select the data points from the reordered sequence of data points based on the magnitudes of the data points with respect to magnitudes of remaining data points from the reordered sequence of data points.

11. The computer-readable storage medium of claim 8, wherein the code in (b) comprises code to apply a matched filter to the data points.

12. The computer-readable storage medium of claim 8, wherein the code in (b) comprises code to identify a first set of data points from the data points as corresponding to the peak.

13. The computer-readable storage medium of claim 12, wherein the code in (b) further comprises code to identify a second set of data points from the data points as corresponding to a spike.

14. The computer-readable storage medium of claim 8, wherein the data points correspond to first data points from the chromatogram, and the computer-readable medium further comprises:

code to apply a regression analysis to second data points from the chromatogram to derive a baseline; and

code to calculate an area of the peak based on the baseline, wherein the area of the peak is indicative of an amount of the analyte.

15. A method of processing mass spectrometry data, comprising:

(a) defining a matched filter based on a sequence of data points; and

(b) applying the matched filter to the sequence of data points to identify a first set of data points from the sequence of data points as corresponding to a peak and to identify a second set of data points from the seciuence of data points as corresponding to a spike, wherein a width of the matched filter corresponds to an expected width of the peak, and the peak is indicative of a presence of an analyte.

18. The method of claim 15, further comprising selecting data points from the sequence of data points based on magnitudes of the data points, and wherein the applying the matched filter in (b) comprises applying the matched filter to the data points to identify the first set of data points from the data points as corresponding to the peak.

16. A method of processing mass spectrometry data, comprising:

(a) defining a matched filter based on a sequence of data points; and

(b) applying the matched filter to the sequence of data points to identify a first set of data points from the seciuence of data points as corresponding to a peak, wherein a width of the matched filter corresponds to an expected width of the peak, and the peak is indicative of a presence of an analyte,

wherein the defining the matched filter in (a) comprises deriving an offset value of the matched filter based on the sequence of data points.

17. The method of claim 16, wherein the offset value comprises an estimated baseline value associated with the sequence of data points.

19. A method of processing mass spectrometry data, comprising:

(a) defining a matched filter based on a sequence of data points;

(b) applying the matched filter to the seciuence of data points to identify a first set of data points from the sequence of data points as corresponding to a peak, wherein a width of the matched filter corresponds to an expected width of the peak, and the neak is indicative of a presence of an analyte;

(c) selecting data points from the sequence of data points based on magnitudes of the data points, wherein the applyina the matched filter in (b) comprises applyina the matched filter to the data points to identify the first set of data points from the data points as corresponding to the peak; and

(d) reordering the sequence of data points, prior to said selecting data points, wherein the sequence of data points is reordered based on magnitudes of the data points.