Dual Ion Trapping in Linear RF Multipole Trap
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Solution Overview
Problem
Current mass spectrometry technologies face challenges in simultaneously confining precursor and reagent ions within a RF field of multipole trapping devices for inducing desired ion/ion reactions, such as electron transfer dissociation (ETD), due to limitations in trapping both cations and anions effectively.
Innovation Solution
A method and system that utilize a 2D linear multipole trap with an additional effective DC gradient to induce ion/ion reactions, allowing for the simultaneous trapping and interaction of positive and negative ions by adjusting the DC gradient and RF potentials, enabling efficient ETD processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If DC biases are applied to rod electrodes to axially confine positive ions in a linear 2D multipole trap, then positive ions are effectively trapped, but negative ions cannot be simultaneously trapped
Solution Approach 1:
The trap is divided into multiple segments along the axial direction, with each segment capable of applying independent DC biases. This segmentation allows different regions to confine different ion polarities simultaneously, resolving the contradiction between trapping positive and negative ions
Solution Approach 2:
The invention transitions from conventional single-polarity trapping to dual-polarity trapping by adding axial segmentation, effectively creating a multi-dimensional trapping configuration that accommodates both cations and anions in different spatial regions
2Productivity
If a DC gradient is applied to enable ion/ion reactions, then ion interaction is improved, but simultaneous trapping of both cations and anions becomes more difficult
Solution Approach 1:
Different DC gradient configurations are applied to different axial segments: regions where ion trapping is prioritized maintain stable potentials, while regions where ion interaction is desired apply gradients to drive reactions, allowing local optimization of both trapping reliability and reaction productivity
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 enhances the capability to perform ETD reactions by allowing for the direct migration and interaction of positive and negative ions within static axial electric fields, improving fragmentation efficiency and signal-to-noise ratios in mass spectrometry.
Implementation Method 1
The RF voltages within such instruments create a pseudo-potential that is charge sign independent
Implementation Method 2
utilize a 2D linear multipole trap with an additional effective DC gradient to induce ion/ion reactions
Implementation Method 3
the applied DC biases can generate electrostatic potentials that axially confine in predetermined sections of the device either positive ions or negative ions
Data Source
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Figure 1B
Figure 2A
AI summary
A novel method and mass spectrometer apparatus is introduced to enable the simultaneous isolation of cations and anions (i.e., precursor and reagent ions) in a linear multipole ion trap via the application of an additional axial DC gradient in combination with coupled RF potential(s). Thus, the combination of the RF and DC voltages in such an arrangement forms a pseudopotential designed to provide for minima for the trapped positively and negatively charged particles that result in the overlap of the ion clouds so as to provide for beneficial ion/ion reactions.