Techniques for mass spectrometry peak list computation using parallel processing

Abstract

Described are techniques for processing data. Sample analysis is performed generating scans of data. Each scan comprises a set of data elements each associating an ion intensity count with a plurality of dimensions including a retention time dimension and a mass to charge ratio dimension. The scans are analyzed to identify one or more ion peaks. Analyzing includes filtering a first plurality of the scans producing a first plurality of filtered output scans. The filtering including first filtering producing a first filtering output, wherein the first filtering includes executing a plurality of threads in parallel which apply a first filter to the first plurality of scans to produce the first filtering output. Each of the plurality of threads computes at least one filtered output point for at least one corresponding input point included in the plurality of scans. Analyzing includes detecting one or more peaks using the filtered output scans.

Description

CROSS REFERENCES TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Application No. 61 / 397,512 filed Jun. 11, 2011 Attorney Docket No. WCS-016PR1 / W-659, and U.S. Provisional Application No. 61 / 437,841 filed Jan. 31, 2011, Attorney Docket No WCS-016PR2 / W-659, both of which are incorporated by reference herein.BACKGROUND[0002]1. Technical Field[0003]This application relates generally to analysis of compounds, and, more particularly, to detection and quantification of ions collected by liquid chromatography, ion-mobility spectrometry and mass spectrometry.[0004]2. Description of Related Art[0005]Mass spectrometers (MS) are used widely for identifying and quantifying molecular species in a sample. During analysis, molecules from the sample are ionized to form ions that are introduced into the mass spectrometer for analysis. The mass spectrometer measures the mass-to-charge ratio (m / z) and intensity of the introduced ions.[0006]Mass spectrometers are limite...

AI Technical Summary

Benefits of technology

The patent describes a method for analyzing data by performing sample analysis and generating scans of data. The scans are then filtered to identify peaks in the data. The filtering is performed by multiple threads in parallel, and the peaks are detected by analyzing the filtered data. The method includes performing first filtering with a smoothing filter and a second derivative filter, and detecting peaks using a threshold. The method also includes selecting scan pack dimensions based on the dimensions of the data and the mass to charge ratio values per scan. The technical effect of the invention is to improve the speed and accuracy of identifying peaks in data analysis.

Problems solved by technology

Mass spectrometers are limited in the number of different ions reliably detected and quantified within a single sample spectrum.

As a result, samples containing many molecular species may produce spectra that are too complex for interpretation or analysis using conventional mass spectrometers.

Moreover, at low concentration, ion detection suffers from background noise and / or interfering background molecules.

Co-elution of peaks from multiple molecules is one possible problem with this method of detecting peaks in a TIC.

Another difficulty encountered with peak detection is detector noise.

Aside from these problems, additional difficulties are encountered when conventional peak detection routines are used to detect chromatographic or spectral peaks.

If performed manually, such conventional methods are both subjective and tedious.

When performed automatically, such methods can still be subjective, due to a subjective selection of thresholds for identification of peaks.

Further, these conventional methods tend to be inaccurate because they analyze data using only a single extracted spectrum or chromatogram, and do not provide ion parameter estimates having the highest statistical precision or lowest statistical variance.

Finally, conventional peak-detection techniques do not necessarily provide uniform, reproducible results for ions at low concentration, or for complex chromatograms, where co-elution and ion interference tend to be common problems.

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