Overlapping Mass Selection Windows in Tandem MS
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Solution Overview
Problem
In tandem mass spectrometry, balancing the number of SWATH experiments, accumulation time, and data points across a peak is challenging, particularly when using narrow mass windows, which can result in insufficient sensitivity or prolonged cycle times, compromising the accuracy and specificity of analysis.
Innovation Solution
The method involves decreasing the widths of the windows in sequential windowed acquisition while increasing the time spent on each window, with overlapping measured mass selection windows to analyze each region multiple times, allowing for wider effective scanning windows while maintaining narrow target windows, thus enhancing sensitivity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If narrow mass window widths are used in SWATH experiments, then selectivity is improved, but sensitivity deteriorates and cycle time increases
Solution Approach 1:
The mass range is divided into multiple overlapping measured windows that collectively cover the target window. Each measured window is scanned separately and the signals are combined computationally to achieve the equivalent of a narrow target window with high sensitivity
Solution Approach 2:
Multiple measured windows are merged through computational combination of their signals. The overlapping regions are summed to enhance sensitivity while the computational processing maintains the selectivity equivalent to a narrow target window
2Measurement precision
If narrow mass window widths are used in SWATH experiments, then selectivity is improved, but productivity deteriorates due to prolonged cycle times
Solution Approach 1:
The scanning task is segmented into multiple measured windows that can be scanned in parallel or sequential fashion, with the computational combination step efficiently merging the results to achieve narrow target window selectivity without the prolonged cycle time
Solution Approach 2:
The system dynamically adjusts the number and positioning of measured windows based on the target window requirements, optimizing the balance between scan time and selectivity for each specific analysis scenario
3Quantity of substance
If wide mass windows are used, then sensitivity is improved, but selectivity deteriorates due to ion interference
Solution Approach 1:
Computational processing acts as an intermediary between the wide measured windows and the narrow target window requirement. The software combines signals from multiple measured windows and applies processing to achieve the selectivity of narrow windows while maintaining the sensitivity benefit of wide windows
Solution Approach 2:
The wide mass range is segmented into multiple overlapping measured windows, each contributing to the final spectrum. This segmentation allows the system to capture sufficient ions (sensitivity) while the computational combination maintains selectivity
Data Source
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AI summary
Systems and methods are provided for analyzing a sample using overlapping measured mass selection window widths. A mass range of a sample is divided into two or more target mass selection window widths using a processor. The two or more target widths can have the same width or variable widths. A tandem mass spectrometer is instructed to perform two or more fragmentation scans across the mass range using the processor. Each fragmentation scan of the two or more fragmentation scans includes a measured mass selection window width. The two or more measured widths of the two or more fragmentation scans can have the same width or variable widths. At least two of the two or more measured mass selection window widths overlap. The overlap in measured mass selection window widths corresponds to at least one target mass selection window width.