Quadrupole Transmission Window Shaping for Uniform SWATH Ion Selection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Not all mass spectrometers can perform sequential windowed acquisition (SWATH) due to non-uniform transmission of precursor ions within a wide precursor mass range, leading to decreased specificity and increased overlap between mass ranges.
Innovation Solution
A method and system that use a processor to select an ion transfer function describing the shape of an effective transmission window, instructing a quadrupole mass filter to create a cumulative transmission window with narrower transmission windows, allowing for tailored ion transmission across precursor mass ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a wide precursor mass range is used to transmit more ions, then sensitivity is increased, but precursor ions of different masses may pass causing ion interference and decreased specificity
Solution Approach 1:
The patent divides a wide precursor mass range into multiple adjacent or overlapping precursor mass ranges (sub-windows). Each sub-window is transmitted separately through the quadrupole mass filter, allowing the system to maintain high sensitivity by covering a wide overall mass range while preserving specificity by isolating individual mass ranges in time. This segmentation approach enables SWATH (Sequential Windowed Acquisition of All Transmitted Homologs) methodology.
Solution Approach 2:
The patent employs dynamic adjustment of the quadrupole mass filter transmission window, rapidly switching between different mass ranges in sequence. The transmission window is dynamically modulated to match the desired effective transmission window shape, allowing the system to adapt between wide coverage (for sensitivity) and precise mass selection (for specificity) on different time scales.
2Adaptability or versatility
If the transmission window shape is non-uniform, then ion transmission varies across the mass range, but this can be corrected by shaping the effective transmission window
Solution Approach 1:
The patent measures the actual transmission characteristics of the quadrupole mass filter and uses this information to calculate correction factors. The system applies feedback control by adjusting the instantaneous transmission window parameters based on the measured effective transmission window shape, enabling correction of non-uniform transmission without requiring complex hardware modifications.
Solution Approach 2:
The patent changes the parameters of the transmission window (width, position, shape) as a function of mass and time to compensate for non-uniform transmission characteristics. By dynamically adjusting these parameters, the system creates an effective transmission window with a desired uniform shape even when the physical transmission window has non-ideal characteristics.
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 sensitivity without sacrificing specificity by shaping the transmission window to uniformly transmit precursor ions, even in mass spectrometers with non-ideal transmission characteristics, thereby optimizing the SWATH method.
Implementation Method 1
instructing a quadrupole mass filter that transmits the precursor ions from a sample
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Systems and methods are provided for shaping an effective transmission window used to select precursor ions for a precursor mass range of a sequential windowed acquisition experiment. For at least one precursor mass range, an ion transfer function is selected that is a function of mass using a processor. A quadrupole mass filter that transmits ions from a sample is instructed to produce two or more transmission windows over time using the processor. The two or more transmission windows are produced to cumulatively create an effective transmission window for the at least one precursor mass range with a shape described by the ion transfer function.