AC Ion Gate for IMS Peak Resolution
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Solution Overview
Problem
Current manufacturing methods for gating devices in ion mobility spectrometers (IMS) fail to effectively improve peak resolution and control ion size injection, leading to inefficiencies in analyzing complex samples with multiple components.
Innovation Solution
The use of interleaved electrically isolated grid elements in the same plane, applying AC voltage to the gate wires to reduce ion depletion area and enhance peak resolution, allowing only specific ions to enter the drift tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional gating devices are used to regulate ion packet injection, then the device structure is simple, but the peak resolution between ions is insufficient and ion size control is poor
Solution Approach 1:
The gating device is segmented into multiple independently controllable gate elements arranged in a grid pattern, allowing selective activation of specific regions to improve ion packet definition and peak resolution while maintaining manageable structural complexity
Solution Approach 2:
The gating device employs dynamic voltage control where gate elements can be selectively activated or deactivated based on ion mobility characteristics, enabling real-time adjustment of ion packet injection and improving resolution through time-dependent gating patterns
2Measurement precision
If traditional DC voltage gating is used, then the gate operation is simple, but the ion depletion area is large which reduces peak resolution
Solution Approach 1:
The gating system employs periodic AC voltage applied to gate elements, creating oscillating electric fields that reduce the static ion depletion area while maintaining effective ion packet regulation, thereby improving peak resolution through dynamic field modulation
Solution Approach 2:
The system changes the voltage parameter from static DC to dynamic AC, and selectively adjusts voltage amplitude and frequency across different gate elements to minimize ion depletion area while maximizing ion packet definition and peak resolution
3Productivity
If conventional gating methods are used, then all ions are allowed to enter the drift tube, but complex samples with multiple components cannot be effectively analyzed
Solution Approach 1:
Different regions of the gating device are assigned different voltage characteristics and gating patterns tailored to specific ion mobility ranges, enabling selective injection of ions with particular properties while filtering out unwanted components, thus improving analysis efficiency for complex samples
Solution Approach 2:
The gating device is designed with multiple independently controllable gate elements that can be configured to perform various gating functions including ion packet formation, ion size selection, and mobility-based filtering, making it adaptable to different sample types and analysis requirements
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 significantly reduces the size of the ion depletion area, improving peak resolution and enabling more precise control over ion injection, thereby enhancing the analysis of complex samples by filtering out lower mobility ions.
Implementation Method 1
By using an AC voltage there is a reduction in the size of the ion depletion area in front of the gate when it is closed, thereby providing a higher peak resolution
Implementation Method 2
The ion gate has a first and second set of electrically isolated grid elements that lie in the same plane where the respective sets of grid elements are applied to alternate potentials
Data Source
AI summary
The present invention uses an AC voltage instead of DC voltage on an ion gate to filter/selectively pass ions. The ions that pass through the AC ion gate can be further separated in a spectrometric instrument. An ion mobility spectrometer using the AC ion gate can achieve better gating performance. For a time of flight ion mobility spectrometer with an AC ion gate, a narrow pulse of selected ions can be passed into a drift tube where they are separated based on their low field ion mobility. Moreover, when the AC voltage at the AC ion gate has a waveform as used for differential ion mobility spectrometry, the time of flight ion mobility spectrometer is converted into a two dimensional separation spectrometer, where ions are first separated based on their high field ion mobility and then further separated based on their low field ion mobility.