Ion Mobility Filter With Varying Channel Gap Widths
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Solution Overview
Problem
Ion mobility spectrometers face challenges in stability and repeatability due to temperature and drift gas pressure variations, leading to inconsistent separation of ions, and there is a need for improved selectivity in distinguishing specific chemicals.
Innovation Solution
An ion filter with multiple channels of varying gap widths is designed, where each channel defines a gap between pairs of electrodes, allowing for increased selectivity and sensitivity by ensuring only target ions pass through both channels, and the arrangement of narrower channels towards the center and wider channels towards the edges encourages even ion flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single ion channel with fixed gap width is used, then the device structure is simple, but the selectivity for distinguishing different chemicals is insufficient
Solution Approach 1:
The ion filter is divided into multiple ion channels (first ion channel, second ion channel, third ion channel, etc.), each with different gap widths. This segmentation allows different ion species to be separated based on their mobility characteristics through channels of varying dimensions, thereby enhancing selectivity without requiring a completely complex new device architecture.
Solution Approach 2:
Each ion channel is assigned a specific local property (gap width) that is optimized for detecting particular ion species. The first ion channel has a first gap width, the second ion channel has a second gap width, and the third ion channel has a third gap width, creating local quality variations that improve overall detection selectivity for different chemicals.
2Measurement precision
If multiple ion channels with different gap widths are used, then the selectivity and sensitivity are improved, but the device complexity increases
Solution Approach 1:
The electrode system is segmented into multiple pairs, with each pair forming a distinct ion channel. The first pair of electrodes forms the first ion channel, the second pair forms the second ion channel, and the third pair forms the third ion channel. This segmentation enables precise control of electric fields in each channel while maintaining a systematic electrode arrangement that manages complexity.
Solution Approach 2:
The ion channels are designed with asymmetric gap widths, where the first gap width differs from the second gap width, and the third gap width differs from both. This asymmetric design creates distinct mobility selection criteria for different ion species, improving measurement precision by enabling differentiation of ions with similar properties through the varying channel geometries.
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 configuration enhances the selectivity and sensitivity of the ion filter, allowing for better separation and identification of target chemicals by ensuring only specific ions pass through without being neutralized, improving the stability and repeatability of ion mobility spectrometry results.
Implementation Method 1
Ion mobility spectrometers are used to detect particular chemicals within gases such as air. Differential mobility spectrometry (DMS) which is also known as field-asymmetric waveform ion mobility spectrometry (FAIMS) is recognised as a powerful tool for separation and characterization of gas-phase ions.
Implementation Method 2
an ion filter for filtering ions from a target chemical in a gas sample, the ion filter comprising: a plurality of electrodes; a first ion channel for filtering ions from a target chemical in the gas sample
Data Source
AI summary
An ion mobility filter is disclosed. The present invention relates to but not exclusively a field asymmetric ion spectrometry filter. For example, we describe an ion filter for filtering ions in a gas sample. The ion filter is comprised of a plurality of electrodes, a first ion channel, and a second ion channel. The first ion channel filters ions from a target chemical in the gas sample, defines a gap between a first pair of electrodes in the plurality of electrodes, and has a first ion channel gap width. The second ion channel filters ions from the target chemical in the gas sample, defines a gap between a second pair of electrodes in the plurality of electrodes, and has a second ion channel gap width. The first ion channel gap width is greater than the second ion channel gap width.