Mass Spectrometer Ion Storage Ejection High-Speed Scanning
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Solution Overview
Problem
Existing mass spectrometers face challenges in reducing instrumental size while maintaining high-speed scanning and sensitivity, particularly when dealing with pulsed ions and collisional cells, which can lead to inaccurate mass spectra and decreased fragmentation efficiency.
Innovation Solution
The implementation of an ion storage-and-ejection system that converts pulsed ion signals into DC current before sampling, allowing for high-speed scanning and maintaining sensitivity by controlling the timing and frequency of ion storage and ejection operations, and optionally using a cooling chamber to reduce ion kinetic energies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the multipole ion guide and collisional cell are shortened to reduce instrument size, then the number of collisions with collision gas decreases, but ion cooling and fragmentation efficiency are hindered
Solution Approach 1:
The patent applies periodic action by introducing collision gas in pulses rather than continuously. The gas introduction is synchronized with ion arrival, creating periodic collision events that maximize fragmentation efficiency while using minimal gas amounts, thereby allowing compact cell dimensions without sacrificing productivity
Solution Approach 2:
The patent changes the temporal parameter of gas introduction from continuous to pulsed mode. By controlling the timing and duration of gas introduction, the system achieves high collision rates in a shortened cell length, resolving the contradiction between compact size and fragmentation efficiency
2Productivity
If a large amount of collision gas is introduced to maintain sufficient collisions in a shortened cell, then the number of collisions is maintained, but the pressure in the latter stage of mass analyzer increases, leading to decreased sensitivity
Solution Approach 1:
By introducing collision gas periodically rather than continuously, the system maintains sufficient collision events for high productivity while allowing pressure to drop between pulses. This temporal separation prevents pressure buildup in the mass analyzer, preserving sensitivity despite high collision rates
Solution Approach 2:
The system performs preliminary action by introducing collision gas just before ions arrive, ensuring collisions occur at the optimal moment. This timing control maximizes collision efficiency without requiring continuous high gas flow, thereby avoiding sensitivity loss from pressure increase
3Speed
If high-speed scanning is performed with pulsed ions, then scanning speed is improved, but mass spectrum accuracy deteriorates due to temporal information loss from pulsed ion arrival
Solution Approach 1:
The patent achieves continuity of useful action by overlapping pulsed ion signals from successive ejecting operations. This overlapping creates an effectively continuous ion stream that maintains high scanning speed while preserving temporal information integrity, thereby achieving both speed and accuracy
Solution Approach 2:
By carefully controlling the periodicity and timing of pulsed ion ejection, the system creates a rhythm where successive pulses overlap constructively. This periodic synchronization ensures that no temporal information is lost while maintaining high scanning throughput
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 enables miniaturization of mass spectrometers while achieving high-speed scanning and maintaining high sensitivity, ensuring accurate mass spectra representation by overlapping pulsed ion signals and optimizing collisional processes.
Implementation Method 1
an ion storage-and-ejection portion for performing a storing operation for storing at least some of the ions generated in the ion source and then performing an ejecting operation for ejecting the stored ions
Implementation Method 2
In the cooling, ions are normally caused to collide with a gas by a multipole ion guide. The collision with the gas lowers the average kinetic energy of the ions and also reduces the range of kinetic energies.
Implementation Method 3
a quadrupole mass filter generating a hyperbolic electric field, produces a selecting voltage by superimposing an RF voltage and a DC voltage on each other, and passes ions of only a desired mass-to-charge ratio
Implementation Method 4
If a gas is introduced into the collisional cell, precursor ions collide against the collision gas, producing fragmentation with a certain probability. As a result, the precursor ions are fragmented in the collisional cell.
Data Source
AI summary
A mass spectrometer and control method which achieves high-speed scanning while maintaining relatively high sensitivity. The mass spectrometer (1) has: an ion source (2); a collisional cell (40) for performing a storing operation for storing at least some of the ions (2) and then performing an ejecting operation for ejecting the stored ions; a second mass analyzer (50) for selecting desired ions; a detector (60) for detecting the desired ions; analog signal processing circuitry (80) for converting a signal from the detector (60) into a voltage; and an A/D converter (90) for sampling and converting the output voltage into a digital signal. Signals delivered from the analog signal processing circuitry (80) in response to two pulsed ions produced by two successive ejecting operations of the collisional cell (40) are at least partially overlapped temporally.