Ion Mobility Spectrometer Dynamic Ejection Control
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Solution Overview
Problem
Conventional ion mobility spectrometers with closed-loop drift regions face challenges in resolving ions of different mobilities, as they undergo varying numbers of cycles, leading to ion mobility-dependent resolution and complications in selective ejection.
Innovation Solution
A method and device that utilize a force applied in the exit region to selectively eject ions based on physicochemical property values, varying the threshold value over time to ensure ions of different values perform the same number of cycles before ejection, independent of their mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ions are caused to perform multiple cycles around a closed-loop drift region to increase effective drift length, then resolution is improved, but ions of different mobilities undergo different numbers of cycles leading to ion mobility-dependent resolution
Solution Approach 1:
The patent applies a time-varying force in the exit region that dynamically adjusts the ejection threshold. This dynamic control allows the system to compensate for the different cycle numbers undergone by ions of different mobilities, ensuring that all ions are ejected after completing the same effective number of cycles, thereby achieving mobility-independent resolution enhancement
Solution Approach 2:
The patent changes the threshold parameter for ion ejection over time. By varying the ejection threshold dynamically, the system can selectively eject ions based on their position in the drift region rather than their mobility, allowing all ions to complete the same number of cycles regardless of their mobility differences
2Measurement precision
If the drift tube length is increased to improve resolution, then measurement precision is improved, but device complexity and length increase
Solution Approach 1:
The patent employs a closed-loop drift region where ions traverse the same physical path multiple times in sequence. This nesting of the drift path allows the effective drift length to be multiplied by the number of cycles without increasing the physical dimensions of the drift tube, achieving resolution enhancement in a compact configuration
Solution Approach 2:
The patent uses periodic cycling of ions through the closed-loop drift region. By causing ions to repeatedly traverse the drift path in periodic cycles, the effective separation distance is extended without requiring a proportionally longer physical tube, thus improving resolution while maintaining compact device dimensions
3Adaptability or versatility
If a force is applied in the exit region to selectively eject ions, then ion separation control is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary force field in the exit region that acts as a mediator between the drift region and the detection region. This force field provides a controllable mechanism for selective ion ejection without requiring complex mechanical or structural modifications to the main drift region, achieving versatile control with minimal added complexity
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 allows for selective ejection of ions based on their physicochemical properties, ensuring consistent resolution and preventing remixing of ions with different mobilities, thereby improving the separation process.
Implementation Method 1
separating ions according to a physicochemical property, such as ion mobility or mass to charge ratio
Implementation Method 2
A conventional ion mobility spectrometer or separator employs a static potential gradient to drive ions along a drift tube
Data Source
AI summary
A method of separating ions according to a physicochemical property is disclosed. The method comprises causing ions to perform a plurality of cycles along or around an ion guiding path such that the ions separate according to said physicochemical property. The ions are ejected from an ion exit region by applying a force to the ions such that only having a physicochemical property value that is either above or below a threshold value are ejected as they pass through the exit region, but ions having a physicochemical property value either below or above said threshold value, respectively, remain within the ion guiding path. The force applied to the ions within the exit region is varied with time such that the physicochemical property value of the ions ejected from the ion guiding region varies with time.