Linear Ion Trap Tapered Electrodes Mass Spectrometry
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Solution Overview
Problem
Conventional ion traps for mass spectrometry face limitations in ion storage volume and efficient ejection due to space charge effects and geometric constraints, leading to degradation in performance, especially when trapping large numbers of ions.
Innovation Solution
A compact ion trap design featuring tapered electrodes with a quadrupole electric field potential that spatially compresses ions according to their mass-to-charge ratio, allowing for efficient ejection orthogonal or parallel to the axis, thereby increasing ion storage volume and ejection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a conventional 3D quadrupole ion trap is used, then the device structure is simple, but the ion storage volume is limited and space charge effects degrade performance when trapping large numbers of ions
Solution Approach 1:
The patent transitions from a conventional 3D quadrupole ion trap to a linear ion trap configuration, effectively changing the dimensional arrangement of electrodes. The linear geometry extends the ion storage region along a linear axis, increasing the available storage volume while reducing ion density and space charge effects through spatial distribution along the linear dimension.
Solution Approach 2:
The linear ion trap divides the ion storage function into multiple electrode segments arranged linearly. The trap consists of multiple electrode pairs (typically four or more) distributed along the linear axis, with each electrode pair contributing to the overall quadrupole field while enabling extended ion confinement along the linear dimension.
2Volume of stationary object
If the ion trap length is increased to increase ion storage volume, then the storage capacity improves, but the device complexity and length increase
Solution Approach 1:
The linear ion trap configuration optimizes the ratio of storage volume to device length by arranging electrodes in a linear geometry. This dimensional arrangement allows the ion storage region to extend efficiently along the linear axis, maximizing volume utilization within a compact longitudinal footprint compared to spherical or elongated 3D configurations.
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
The design enhances ion trap performance by increasing ion storage capacity and ejection efficiency, enabling high-resolution, high-sensitivity mass spectrometry with improved sensitivity and speed, capable of multiplexing MS/MS experiments without signal loss.
Implementation Method 1
an arm having a first end and a second end for confining and spatially compressing the ions, and an ejection port for ejecting the spatially compressed ions from the second end of the arm of the ion trap. The arm includes two pairs of opposing electrodes between the first end and the second end. Each electrode includes an interior surface suitably shaped for providing a quadrupole electric field potential
Implementation Method 2
Because the kinetic energy of ions injected into an ion trap decreases in collisions with buffer gas molecules, usually helium, the injected ions naturally localize at the minimum of the potential well
Data Source
AI summary
A method for manipulating ions in an ion trap includes storing ions, spatially compressing, and ejecting selected ions according to mass-to-charge ratio. An ion trap includes an injection port, an arm having a first and a second end for confining and spatially compressing the ions, and an ejection port for ejecting the ions from the second end. The arm includes two pairs of opposing electrodes, which provide a quadrupole electric field potential at any cross-section of the ion trap. The distance between opposing electrodes and the cross-sectional area of the electrodes increases from the first to second end. The electrodes may be tapered cylindrical rods or of hyperbolic cross-section. Ions selected for ejection are spatially compressed into a region at the second (wider) end. The ion trap may include one arm, with either orthogonal or axial ejection, or two arms with a central insert for orthogonal ejection.