Linear RF Ion Trap with Dual Voltage for ETD Fragmentation
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Solution Overview
Problem
Current linear ion traps for electron transfer dissociation (ETD) fragmentation have limitations in fragmentation yield and are difficult to fill with ions, compared to three-dimensional ion traps, which are more complex and expensive to operate.
Innovation Solution
A linear RF ion trap with a new electronic power configuration, using two RF voltages applied to the pole rods, creates axial pseudopotential barriers with a single maximum, allowing for efficient trapping and fragmentation of both positive and negative ions, improving fragmentation yield and ease of filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a linear RF ion trap is used for electron transfer dissociation (ETD) fragmentation, then the device complexity is reduced compared to three-dimensional ion traps, but the fragmentation yield is lower and the trap is difficult to fill with ions
Solution Approach 1:
The patent applies dynamic voltage configuration to the pole rods, switching between different RF voltage patterns (standard quadrupole mode and specialized fragmentation mode) to optimize performance for different operational requirements. This dynamic adjustment allows the linear trap to achieve high fragmentation yield for ETD while maintaining operational simplicity
Solution Approach 2:
The invention changes the electrical parameters (RF voltage amplitude, frequency, and phase relationships) applied to the pole rods to create optimal conditions for electron transfer dissociation. By adjusting these parameters, the trap achieves enhanced fragmentation yield without increasing physical complexity
2Device complexity
If a linear RF ion trap is used for electron transfer dissociation (ETD) fragmentation, then the device complexity is reduced compared to three-dimensional ion traps, but the ease of filling with ions is worsened
Solution Approach 1:
The system dynamically adjusts the RF voltage configuration and axial electric field to create favorable potential well conditions for ion capture. This dynamic control enables easy filling of the trap with ions while maintaining the simplicity of linear geometry
Solution Approach 2:
By changing the electrical parameters (axial field strength, RF voltage settings) the trap creates optimal conditions for ion injection and trapping efficiency, making it easy to fill with ions despite the simplified linear structure
3Productivity
If axial pseudopotential barriers with single maximum are created in a linear ion trap, then the fragmentation yield for ETD is enhanced, but the device complexity increases due to additional RF voltage configuration
Solution Approach 1:
The existing pole rods in the linear ion trap are made multi-functional by applying different RF voltage configurations. The same hardware structure serves both as radial confinement electrodes and as means to create axial pseudopotential barriers, avoiding additional complex components while enhancing fragmentation yield
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 configuration enhances the fragmentation yield for ETD and collision-induced fragmentations, making it easier to fill the ion trap while maintaining high-quality fragment ion production, suitable for both ETD and ergodic fragmentations.
Implementation Method 1
A second RF voltage is applied either single-phase to some of the pole rods, but not to all of them, or dual-phase to unequal numbers of pole rods. This second RF voltage causes the axis potential of the ion storage device to oscillate at RF frequency with respect to the potential of the surroundings and generates the desired axial pseudopotential barriers at the ends of the ion storage device
Implementation Method 2
The two phases of a first RF voltage are applied to the pole rods alternately around the circumference, and serve to confine positive as well as negative ions in the radial direction
Data Source
AI summary
The invention relates to a linear multipole ion storage device which is suitable for reactions between positive and negative ions, and for fragmentation reactions by electron transfer dissociation (ETD) in particular. The invention uses a linear RF ion trap with at least three pairs of rods with a new type of electronic power supply. The two phases of a first RF voltage are applied to the pole rods alternately around the circumference and confine positive as well as negative ions in the radial direction. A second RF voltage is either applied single-phase to some of the pole rods, but not to all of them, or two-phase to unequal numbers of pole rods so that the axis potential oscillates with the frequency of this second RF voltage and generates a pseudopotential barrier which acts axially on ions of both polarities at the ends of the ion storage device. In the interior, the second RF produces a complex superposition field resulting in an increased fragmentation yield for ETD.