Ion Guide Pole Switching for Mass Spectrometry
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Solution Overview
Problem
Conventional mass spectrometry devices face difficulties in rapidly switching the effective number of poles in multipole ion guides, leading to inefficiencies in ion transport and analysis, especially when dealing with a wide range of mass-charge ratios, due to the need for adjusting resonant circuits and laborious switching operations.
Innovation Solution
An ion guide with a voltage generating means that produces square wave voltages and a connection switching means allowing for rapid switching between different configurations of electrode sets, enabling the effective number of poles to be changed without altering the frequency and amplitude of the voltages, thus allowing for efficient ion transport across a wide mass-charge ratio range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the effective number of poles is increased to improve ion confinement capacity, then ion confinement potential increases, but the mass cutoff increases making it difficult to transport low mass-charge ratio ions
Solution Approach 1:
The ion guide employs dynamic switching between different multipole configurations (quadrupole, hexapole, octupole) by rapidly changing the voltage application pattern to N electrodes. This allows the system to adapt its ion confinement characteristics in real-time, selecting the appropriate pole number based on the mass-charge ratio of ions being analyzed, thereby resolving the contradiction between strong confinement and broad mass range coverage
Solution Approach 2:
The system changes the effective number of poles by modifying the voltage application parameters - specifically, applying high frequency voltages to different combinations of electrodes to create quadrupole (4 poles), hexapole (6 poles), or octupole (8 poles) configurations. This parameter change allows the same physical electrode structure to provide different confinement strengths suitable for different mass ranges
2Adaptability or versatility
If conventional switching methods are used to change the number of poles, then pole configuration can be changed, but switching speed is slow due to resonant circuit adjustment requirements
Solution Approach 1:
The invention extracts the resonant circuit adjustment requirement from the pole switching process. By pre-configuring multiple resonant circuits with different resonant frequencies and selectively connecting them, the system eliminates the need to adjust resonant frequencies during switching. Only simple on/off switching of the resonant circuits is required, dramatically increasing switching speed while maintaining pole configuration flexibility
Solution Approach 2:
The system performs preliminary configuration by setting up multiple resonant circuits with predetermined resonant frequencies before switching is needed. Each resonant circuit is pre-tuned to work with a specific pole configuration, so when switching is required, the system only needs to activate the appropriate pre-configured circuit without any time-consuming adjustments
3Device complexity
If a fixed pole number is used in the ion guide, then the structure is simple, but the system cannot efficiently handle wide mass-charge ratio ranges
Solution Approach 1:
The ion guide uses segmentation by dividing the electrode system into N individually addressable electrodes that can be grouped into different multipole configurations. Instead of using a single fixed pole structure, the electrodes are segmented and reconfigurable, allowing the system to maintain relatively simple individual electrode structures while achieving complex reconfigurable functionality for wide mass range coverage
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
Enables nearly real-time switching of the ion guide's effective number of poles, minimizing non-sensing time and allowing for efficient ion capture and transport, regardless of the mass-charge ratio range, thereby improving analysis results.
Implementation Method 1
When this sort of high frequency voltage is applied to each rod electrode, pseudo-potential barriers are formed by the high frequency electric field generated between the electrodes, and ions are reflected between these potential barriers as they travel downstream.
Implementation Method 2
a connection switching means which has one or more sets of two or more circumferentially adjacent electrodes from among said N electrodes... and which switches the electrical connection between electrodes of said voltage generating means and said electrode unit
Data Source
AI summary
An electrode changeover switch which switches the connection state of electrodes is provided in the wiring path between eight electrodes through, arranged rotation-symmetrically about ion optical axis, and voltage generation switch which generates square wave high voltage ±V. When switch is switched as shown in the drawing, two circumferentially adjacent rod electrodes are connected to form one set, a square wave voltage of opposite phase is applied to circumferentially adjacent sets, and an effectively quadrupole electric field is formed. When switch is switched, a square wave voltage of opposite phase is applied to circumferentially adjacent rod electrodes and an octupole electric field is formed. In this way, by switching the switch according to the mass range, etc., it becomes possible to rapidly switch the number of poles of a multipole electric field and to suitably transport ions.