Variable m/z Isolation Windows for Mixed Spectra Deconvolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional SWATH ™< acquisition methods in tandem mass spectrometry face challenges in identifying precursor ions when multiple precursor ions are present in the same mass selection window and deconvolving product ions with shared mass-to-charge ratios, leading to convolution of product ion intensities.
Innovation Solution
The system dynamically changes the mass-to-charge ratio (m/z) range of precursor ion mass selection windows among cycles, using a processor to perform precursor ion survey scans and adjust window ranges to ensure that each precursor ion remains in one window while others are shifted to another, allowing for distinct identification and deconvolution of product ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed precursor ion mass selection window is used in SWATH acquisition, then the method is simple and reproducible, but multiple precursor ions in the same window cause convolution of product ion intensities and prevent accurate identification
Solution Approach 1:
The patent applies dynamics by making the precursor ion mass selection window variable rather than fixed. The window dynamically shifts its m/z range between successive cycles based on a predetermined shifting pattern, allowing the same physical window to selectively capture different precursor ions at different times. This resolves the contradiction by maintaining the simplicity of a fixed window approach while adding temporal variability to enable precursor ion identification through deconvolution of product ion spectra.
2Measurement precision
If a narrow precursor ion mass selection window is used, then the likelihood of multiple precursors in the window is small, but the coverage of the precursor mass range requires many more windows and cycles
Solution Approach 1:
The patent applies periodic action by implementing a cyclic shifting pattern where the precursor ion mass selection window moves through the precursor mass range in a systematic, repeating sequence. Instead of using many narrow windows sequentially, the same window periodically visits different m/z regions in a predetermined pattern, allowing comprehensive coverage to be achieved through temporal repetition rather than spatial multiplication. This maintains measurement precision while improving productivity by reducing the total number of windows and cycles needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the ability to identify and deconvolve product ions by altering the precursor ion mass selection windows, reducing convolution and improving the accuracy of precursor ion information in tandem mass spectrometry experiments.
Implementation Method 1
an ion source configured to receive the one or more compounds from the sample introduction device and ionize the one or more compounds, producing an ion beam of precursor ions
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An m/z range of an ion beam is divided into two or more precursor ion mass selection windows. A pattern of two or more different window m/z ranges to be used during two or more successive cycles for at least one precursor ion mass selection window is determined. The pattern includes an initial window m/z range and one or more successively different window m/z ranges. Each of the one or more successively different window m/z ranges includes at least a portion of the initial window m/z range. A tandem mass spectrometer is instructed to select and fragment the two or more precursor ion mass selection windows during each cycle of a plurality of cycles and to repeatedly use the pattern for each group of two or more successive cycles of the plurality of cycles for the selection and fragmentation of the at least one precursor ion mass selection window.