Forked Ion Guide Electrodes for Mass Spectrometry Contamination
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Solution Overview
Problem
Ion guides in mass spectrometers are prone to contamination due to rejected ions hitting the electrode surfaces, leading to electric potential barriers that distort ion motion and deteriorate instrument performance, with existing solutions like heating or cleaning being complex or reducing uptime.
Innovation Solution
The ion guide electrodes are designed with forked or recessed features at the entrance end, allowing rejected ions to pass through gaps or offset surfaces, minimizing contact with sensitive electric potential defining surfaces and reducing contamination, while maintaining effective ion transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ion guide electrodes are used, then ion transmission is achieved, but rejected ions hit the electrode surfaces causing contamination and performance deterioration
Solution Approach 1:
The electrode surface is segmented into multiple zones with different potentials (conductive zone, intermediate zone, insulating zone), creating a stepped potential distribution that guides rejected ions away from the electrode surface through vertical electric field gradients
Solution Approach 2:
An intermediate conductive zone with moderate potential is introduced between the high-potential insulating zone and the low-potential conduction zone, serving as a transition region that facilitates smooth ion trajectory deflection without abrupt potential changes
2Reliability
If heating or cleaning methods are used to remove contamination, then electrode performance is restored, but device complexity increases or uptime is reduced
Solution Approach 1:
The anti-contamination electrode structure proactively prevents contamination formation from the outset by deflecting rejected ions away from the electrode surface, eliminating the need for subsequent cleaning operations
Solution Approach 2:
The electrode system self-regulates by using its own electric field configuration to prevent contamination, without requiring external heating elements, cleaning mechanisms, or additional control systems
3Productivity
If electrode surfaces are exposed to rejected ions, then ion guide operation is maintained, but deposits form creating electric potential barriers that distort ion motion
Solution Approach 1:
Different zones of the electrode surface are assigned different functional qualities: the conduction zone provides ion transport, the intermediate zone provides trajectory deflection, and the insulating zone provides additional deflection and protection, creating a spatially varying functional structure
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 design significantly reduces contamination, prolongs ion guide uptime, and maintains high transmission efficiency for a wide mass range without the need for frequent cleaning or heating, thereby enhancing the performance and productivity of mass spectrometers.
Implementation Method 1
a radio frequency voltage generator applying radio frequency voltages to the plurality of electrodes for radially confining ions
Implementation Method 2
allowing rejected ions to pass through gaps or offset surfaces, minimizing contact with sensitive electric potential defining surfaces
Data Source
Figure 1~2
Figure 3
Figure 4~4A
AI summary
The invention relates to a radio frequency ion guide construction for use in mass spectrometry that minimizes contamination by allowing ions rejected by the RF confinement field to fly through and away from the ion guide electrodes and preventing them from hitting the sensitive electric potential defining surfaces of the ion guide electrodes. At the entrance end of the ion guide, each electrode of the plurality of electrodes has a front end that is forked or that contains a recessed feature facing an interior of the ion guide. For an electrode that is forked, the teeth of the forked end may have different shapes or tapers, and a conductive mesh may be used to cover a gap between the teeth. Similarly, for an electrode that has a recessed feature, a conductive mesh may cover the recessed feature.