Tandem Mass Spectrometry Ion Ejection Control
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Solution Overview
Problem
Current tandem mass spectrometry methods face limitations in efficiently analyzing samples due to the need for large quantities of precursor ions and challenges in dynamically ranging parallel ion accumulation and sequential ejection, which restricts the instrument's duty cycle and analytical capabilities.
Innovation Solution
The method involves injecting ions into a device capable of serial ejection using a pseudopotential barrier generated by an RF voltage, filtering ions upstream to manage m/z-dependent accumulation, and sequentially ejecting ions based on their mass-to-charge ratios for individual analysis, allowing for improved dynamic range and predictable ejection without relying on ion mobility measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If parallel ion accumulation is used to increase sensitivity, then the quantity of precursor ions is improved, but the dynamic range control becomes difficult and the ejection timing becomes unpredictable
Solution Approach 1:
The patent segments the continuous ion beam into discrete m/z-dependent groups using a quadrupole mass filter with notched isolation waveforms. This segmentation allows precise control over which ion species are accumulated and when they are ejected, resolving the dynamic range control issue while maintaining high ion quantities through parallel accumulation of multiple m/z windows.
Solution Approach 2:
The patent applies preliminary filtering and sorting of ions by m/z ratio before accumulation using the quadrupole mass filter. By pre-organizing ions into discrete m/z groups with notched isolation waveforms, the system ensures predictable ejection timing and accurate dynamic range control while still accumulating large quantities of ions in parallel.
2Measurement precision
If sequential ejection of ions is implemented to improve dynamic range, then the measurement precision is improved, but the spectral acquisition time increases
Solution Approach 1:
The patent implements periodic ejection of ion groups based on their m/z ratios using synchronized notched isolation waveforms. Multiple m/z windows are accumulated in parallel and then ejected in a periodic sequence, maintaining predictable timing relationships that minimize spectral acquisition time while preserving accurate dynamic range control.
Solution Approach 2:
The patent maintains continuous ion accumulation across multiple parallel m/z windows rather than sequentially processing single ions. The quadrupole mass filter continuously filters and accumulates ions from multiple m/z ranges simultaneously, and the synchronized ejection mechanism ensures continuous useful action with minimal idle time between acquisitions.
3Adaptability or versatility
If ion mobility measurements are used for ejection control, then the separation capability is improved, but the device complexity and requirement for additional measurements increases
Solution Approach 1:
The patent extracts the m/z ratio information directly from the quadrupole mass filter's native filtering capability and uses it for ejection control. By taking out and utilizing the already-measured m/z ratios through notched isolation waveforms, the system achieves precise separation and ejection control without adding ion mobility measurement devices or complexity.
Solution Approach 2:
The quadrupole mass filter performs self-service by using its own m/z filtering capability to both select ions for accumulation and control their ejection timing. The notched isolation waveforms leverage the filter's inherent mass selection property, eliminating the need for separate ion mobility measurement systems and reducing overall device complexity.
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 mass spectrometer's duty cycle by reducing average spectral acquisition times and improving sensitivity, enabling more efficient analysis of complex samples with better dynamic range and applicability to uncharacterized molecules.
Implementation Method 1
injecting ions into a device capable of serial ejection using a pseudopotential barrier generated by an RF voltage
Implementation Method 2
filtering ions upstream to manage m/z-dependent accumulation
Data Source
AI summary
A method for parallel accumulation and serial fragmentation of ions, wherein ions are injected into a device capable of serial ejection using a pseudopotential barrier created by an RF voltage. In all instances, the ions may be filtered prior to accumulation in the device capable of serial ejection. In some cases this filtering may take the form of discrete isolation windows using isolation waveforms with multiple notches. In some cases these waveforms may be applied to a quadrupole mass filter. Following accumulation of the precursor ions, the initial population may be serially ejected using a pseudopotential barrier created by an RF voltage. Following serial ejection, the individual precursor ion populations are analyzed. In some cases, this analysis might involve additional rounds of ion isolation and manipulation (e.g., MSn, CID, ETD, etc.).