Closed Path Ion Mobility Spectrometer with Hybrid Drift Tubes
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Solution Overview
Problem
Conventional ion mobility spectrometers face limitations in resolving ion peaks within a specific ion mobility range due to the limited length of single-pass drift tubes, leading to overcrowding and inadequate separation of ions.
Innovation Solution
A hybrid ion mobility spectrometer is designed with a combination of single-pass and multiple-pass drift tubes, along with controllable ion steering channels, allowing ions to traverse both drift tubes sequentially, enabling additional separation based on different ion mobility functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single-pass drift tube is used, then the device complexity is low, but the resolution of ion peaks is insufficient due to limited separation length
Solution Approach 1:
The drift tube is divided into multiple segments or passes, allowing ions to traverse the same separation region multiple times. This segmentation approach extends the effective separation length without proportionally increasing the physical device length, thereby improving ion peak resolution while controlling device complexity.
Solution Approach 2:
The multiple-pass drift tube design nests additional drift regions within the overall device structure, where ions sequentially pass through nested drift tube sections. This nesting allows the system to achieve extended separation capability within a compact configuration, improving resolution without linearly increasing device complexity.
2Measurement precision
If the drift tube length is increased to improve separation, then the resolution of ion peaks improves, but the loss of time increases due to longer ion travel time
Solution Approach 1:
The system dynamically switches between single-pass and multiple-pass modes depending on the specific analytical requirements. This dynamic configuration allows optimization of the balance between separation quality and analysis time, adjusting the ion path length based on the complexity of the ion mixture being analyzed.
Solution Approach 2:
The system changes operational parameters such as the number of passes through the drift tube, electric field strength, and buffer gas composition to optimize both separation resolution and analysis time. By adjusting these parameters, the system achieves improved ion separation without excessive time penalty.
3Measurement precision
If a hybrid configuration with both single-pass and multiple-pass drift tubes is used, then the resolution and ion concentration are improved, but the device complexity increases
Solution Approach 1:
The hybrid drift tube system provides multiple functions within a single device: it can operate in single-pass mode for rapid analysis and in multiple-pass mode for high-resolution separation. This multi-functionality allows the system to address diverse analytical requirements without requiring separate dedicated instruments, justifying the increased device complexity through enhanced versatility.
Solution Approach 2:
Ion steering channels act as intermediaries that control the flow of ions between the single-pass and multiple-pass drift tube sections. These intermediary elements enable selective routing of ions based on their separation progress, allowing the system to achieve high resolution while maintaining controlled complexity through intelligent ion management.
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 resolution of ion peaks by allowing ions to undergo multiple passes through the multiple-pass drift tube, improving the separation of ions within the ion mobility range of interest and increasing ion concentration.
Implementation Method 1
an electric drift field is established in a drift tube filled with a buffer gas, and as the ions move through the drift tube under the influence of the electric drift field the ions collide with the buffer gas and separate as a function their collision cross-sections
Implementation Method 2
an ion steering channel controllable to selectively pass ions traveling through the single-pass drift tube into the multiple-pass drift tube
Data Source
AI summary
An ion mobility spectrometer includes a drift tube responsive to application of at least a first voltage to establish a first electric field therein configured to cause ions within the drift tube to move along and about the drift tube while separating from one another as a function of ion mobility, and a transition region coupled to opposed ends of the first drift tube such that the drift tube and the transition region together define a closed path. The transition region is responsive to application of at least a second voltage to cause the ions to move along and about the closed path, to application of at least a third voltage to selectively pass ions into the drift tube and to application of at least a fourth voltage to selectively pass ions out of the drift tube.