Closed Loop Ion Guide for High Resolution Separation
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Solution Overview
Problem
Conventional ion mobility spectrometers require long drift regions and high voltages to achieve high resolution, leading to hazardous electrical discharges and large device sizes.
Innovation Solution
A closed loop ion guide with a moving DC voltage gradient that maintains a high electric field strength over a shorter region, allowing ions to cycle multiple times while minimizing the use of high voltages and reducing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electric field strength is increased to improve resolution, then the resolution increases, but electrical breakdown occurs in the drift gas
Solution Approach 1:
The patent applies a non-uniform electric field where the field strength is locally enhanced in specific regions through strategically placed electrodes. This allows high field strength (for good resolution) to be achieved locally without requiring high field strength throughout the entire drift region, thereby avoiding electrical breakdown while maintaining measurement precision.
Solution Approach 2:
The patent employs dynamic control of electrode voltages to create a time-varying electric field configuration. By dynamically adjusting the field distribution, the system can achieve high resolution separation without sustaining continuously high field strengths that would cause electrical breakdown, thus resolving the contradiction between resolution and reliability.
2Measurement precision
If the length of the drift region is increased to improve resolution, then the resolution increases, but the device size and potential difference increase
Solution Approach 1:
Instead of uniformly extending the drift region length, the patent concentrates the electric field action in specific localized zones within a compact drift region. This allows effective ion separation and high resolution to be achieved without proportionally increasing the overall device length, as the separation occurs primarily in regions with optimized field strength rather than requiring a long uniform field throughout.
Solution Approach 2:
The patent transitions from relying solely on extending the drift region length (one dimension) to achieving resolution enhancement through spatial optimization of field distribution across multiple dimensions. By carefully positioning electrodes in three-dimensional space and creating complex field geometries, the system achieves high resolution in a more compact overall structure.
3Measurement precision
If the drift region length is increased to maintain electric field strength, then the resolution improves, but high absolute voltages are required which may result in hazardous electrical discharges
Solution Approach 1:
The patent creates localized high field strength regions through specific electrode configurations rather than applying high voltages across the entire drift region. This allows the necessary electric field strength for high resolution to be achieved in localized zones without requiring high absolute voltages across the whole system, thereby reducing the risk of hazardous electrical discharges while maintaining measurement precision.
Solution Approach 2:
The drift region is effectively segmented into multiple zones with different electric field characteristics through the use of multiple electrodes. This segmentation allows the total voltage requirement to be distributed across several smaller potential differences between adjacent electrodes, achieving the necessary local field strength without requiring high absolute voltages that would create safety hazards.
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 increases resolution without the need for lengthy devices or high voltages, enhancing sensitivity and safety by maintaining a high electric field strength over a compact geometry.
Implementation Method 1
separate ions according to their ion mobilities through the drift gas
Implementation Method 2
a DC voltage gradient is maintained along a portion of the length of the drift region at any given time
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
An ion mobility separator (4) and a method of separating ions according to their ion mobility are disclosed. An RF ion guide is provided having a plurality of electrodes (8) that are arranged to form an ion guiding path that extends in a closed loop. RF voltages are supplied to at least some of the electrodes (8) in order to confine ions within said ion guiding path. ADC voltage gradient is maintained along at least a portion of a longitudinal axis of the ion guide, wherein the voltage gradient urges ions to undergo one or more cycles around the ion guide and thus causes the ions to separate according to their ion mobility as they pass along the ion guide. The closed loop ion guide enables the resolution of the ion mobility separator to be increased without necessitating a large device, since the drift length through the device can be increased by causing the ions to undergo multiple cycles around the device.