Ion Trap Sequential Windowed Acquisition for Mass Spectrometry
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Solution Overview
Problem
High-resolution and high-throughput quadrupole time-of-flight mass spectrometry instruments face limitations in duty cycle efficiency due to time-consuming mass filtering steps and ion wastage, especially when ion flux is low, making it difficult to achieve the desired signal-to-noise ratio for the entire mass range.
Innovation Solution
The implementation of sequential windowed acquisition using an ion trap, where the mass filtering step is performed once and mass windows are selected by ejecting ions from the ion trap, significantly reducing the overall acquisition time and improving duty cycle efficiency by almost five times compared to quadrupole time-of-flight methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If quadrupole time-of-flight mass spectrometry is used for sequential windowed acquisition, then mass range scanning is achieved, but duty cycle efficiency is limited due to time-consuming mass filtering steps
Solution Approach 1:
The patent replaces the mechanical mass filtering system (quadrupole) with a different physical principle (ion trap storage and selective ejection). Ions are trapped in the ion trap and selectively ejected based on their mass-to-charge ratio, eliminating the need for continuous mechanical filtering and significantly improving duty cycle efficiency
Solution Approach 2:
The patent performs preliminary ion trapping and storage before analysis. By collecting ions in the ion trap first and then performing selective ejection for different mass windows, the system avoids repeated filtering operations and achieves faster data collection across the entire mass range
2Quantity of substance
If sequential windowed acquisition is performed with multiple mass windows, then complete mass range coverage is achieved, but ion wastage increases due to repeated mass filtering
Solution Approach 1:
The patent recovers ions that would otherwise be wasted in sequential filtering. By trapping ions in the ion trap and selectively ejecting them for different mass windows, the system reuses the same ion population multiple times, dramatically improving ion utilization efficiency
Solution Approach 2:
The ion trap serves multiple functions: it acts as both an ion storage device and a mass selection device. This multi-functionality eliminates the need for separate filtering stages and allows the same trapped ions to be analyzed across multiple mass windows
3Measurement precision
If low ion flux is present in the source, then signal-to-noise ratio deteriorates, but ion trap accumulation can compensate by concentrating ions before analysis
Solution Approach 1:
The ion trap performs preliminary ion accumulation and concentration before the actual mass analysis. By trapping and concentrating ions over time, the system compensates for low ion flux from the source and ensures sufficient ion counts for high signal-to-noise ratio spectra
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 allows for faster data collection, achieving a nearly five-fold increase in duty cycle efficiency, enabling the acquisition of high-quality spectra across the entire mass range with reduced ion wastage and improved signal-to-noise ratio, particularly when ion flux is low.
Implementation Method 1
a mass spectrometer to collect in an ion trap a plurality of ions within a selected mass range
Implementation Method 2
detect a mass spectrum of the ejected ions of each mass window with a mass analyzer, producing a collection of mass spectra
Data Source
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AI summary
Systems and methods are provided to perform sequential windowed acquisition of mass spectrometry data. A mass range and a mass window width parameter are received for a sample. A plurality of ions from the sample that are within the mass range are collected in an ion trap of a mass spectrometer. Two or more mass adjacent or overlapping windows are calculated to span the mass range using the mass window width parameter. Ions within each mass window are ejected from the ion trap. A mass spectrum is then detected from the ejected ions of the each mass window with a mass analyzer of the mass spectrometer, producing a collection of mass spectra for the mass range. The two or more mass windows can all have the same width, can all have different widths, or can have at least two mass windows with different widths.