2D Ion Trap Multi-Polarity Trapping via Dynamic Axial Fields
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Solution Overview
Problem
Current 2D ion traps cannot simultaneously trap positive and negative ions due to the repulsive DC field's attractive nature for ions of opposite polarity, preventing simultaneous trapping and reaction in the same region.
Innovation Solution
A method involving an ion guide with RF voltage potential for radial confinement and DC voltage barriers of the same polarity as each ion group, along with axial fields to push ions toward trapping barriers, allowing for separate trapping regions or alternating axial field directions to trap ions of opposite polarities effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC field is applied at the entrance and exit of a 2D ion trap to prevent ions from leaving along the axis, then ions of one polarity are effectively trapped, but ions of the opposite polarity are attracted by the repulsive field and lost from the trap
Solution Approach 1:
The patent applies dynamic axial fields that alternate in direction at a frequency matching the ion oscillation frequency. This dynamic approach allows the field to repel ions of one polarity during part of the cycle while attracting ions of the opposite polarity during another part, effectively trapping both polarities simultaneously. The field transitions from static to dynamic to resolve the polarity selectivity issue.
Solution Approach 2:
The patent employs periodic axial fields that oscillate at the ion oscillation frequency to trap ions of both polarities. The periodic reversal of the field direction ensures that ions of either polarity experience a net repulsive force over each cycle, preventing them from escaping while maintaining trapping effectiveness for both polarities.
2Adaptability or versatility
If a 3D ion trap is used to trap ions of both polarities simultaneously, then reactions between positive and negative ions can occur, but the trapping volume is limited compared to 2D ion traps
Solution Approach 1:
The patent combines the axial confinement capability of 2D traps with dynamic field control to achieve 3D-like trapping of both polarities. By using dynamic axial fields in addition to radial RF confinement, the system effectively creates a three-dimensional trapping region that maintains the large volume advantage of 2D traps while enabling multi-polarity trapping.
3Device complexity
If only one polarity of ions is trapped and analyzed at a time in a 2D ion trap, then the trapping and analysis are simple, but reactions between positive and negative ions cannot occur
Solution Approach 1:
The patent uses dynamic axial fields that can be controlled in amplitude and frequency to manage the trapping of different ion polarities. By adjusting the field parameters, the system can trap both polarities simultaneously or sequentially, enabling ion reactions while maintaining relatively simple control mechanisms.
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 the simultaneous trapping and analysis of both positive and negative ions in a 2D ion trap, facilitating reactions and partial charge neutralization, similar to 3D ion traps, while maintaining a larger trapping volume.
Implementation Method 1
applying an RF voltage potential to the first ion guide for confining the first group of ions and the second group of ions radially within the first ion guide
Implementation Method 2
providing a trapping barrier to the second end of the first ion guide for trapping the first group of ions within the first ion guide, wherein the trapping barrier is a DC voltage barrier of the same polarity as the first group of ions
Implementation Method 3
providing an axial field for pushing the first group of ions toward the trapping barrier and for pushing the second group of ions toward the first end
Data Source
AI summary
A method of analyzing ions is provided having a first ion guide with first and second ends and introducing a first group of ions and a second group of ions of opposite polarity into the first ion guide, and applying an RF voltage potential to the first ion guide for confining the first and second groups of ions radially within the first ion guide. A first trapping barrier is provided to the first end of the first ion guide for trapping the first group of ions within the first ion guide and a second trapping barrier is provided to the second end of the first ion guide for trapping the second group of ions within the first ion guide and an axial field is provided for pushing the first group of ions toward the first trapping barrier and pushing the second group of ions toward the second trapping barrier.