Hybrid Ion Mobility Spectrometer with Multiple-Pass Drift Tube
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Solution Overview
Problem
Conventional ion mobility spectrometers face limitations in resolving ions with similar mobilities, as they can only separate ions based on a single function of ion mobility, leading to overcrowding of ion intensity peaks within the drift tube length, which hampers accurate analysis.
Innovation Solution
A hybrid ion mobility spectrometer is designed with a combination of single-pass and multiple-pass drift tubes, where ion gates control the passage of ions between the two tubes, allowing for additional separation based on a second function of ion mobility, enabling ions to traverse the multiple-pass drift tube multiple times, thereby enhancing resolution of overlapping peaks.
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 measurement precision of ion mobility separation is insufficient
Solution Approach 1:
The drift tube system is segmented into multiple functional sections: a first drift tube for initial ion separation, a second drift tube for additional separation stages, and intermediate regions with ion gates. This segmentation allows each section to contribute differently to the overall separation process, improving measurement precision while maintaining manageable device complexity through modular design.
Solution Approach 2:
The patent implements a nested drift tube configuration where the second drift tube is positioned within or alongside the first drift tube structure. Ions traverse the first drift tube, then are directed into the second drift tube for further separation, and finally exit through the first drift tube's outlet. This nesting approach maximizes separation precision by effectively increasing the separation path length without proportionally increasing the external device footprint.
2Measurement precision
If the drift tube length is increased to improve separation, then the measurement precision improves, but the loss of time increases
Solution Approach 1:
The ion gates in the intermediate regions are controlled to open and close periodically, creating a gating sequence that directs ions through the first drift tube, then into the second drift tube, and finally out through the first drift tube's outlet. This periodic gating action enables ions to traverse an extended effective path length for improved separation resolution while maintaining a compact physical structure that reduces overall transit time compared to a linearly extended single-pass tube.
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 allows for improved separation and analysis of ions with similar mobilities by utilizing the multiple-pass drift tube to further resolve ions that were not adequately separated in the single-pass tube, enhancing the accuracy of ion mobility spectral information.
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
Data Source
AI summary
A hybrid ion mobility spectrometer includes a single-pass drift tube having an ion inlet at one end and an ion outlet at an opposite end, a multiple-pass drift tube having an ion inlet and an ion outlet each coupled to the single pass drift tube between the ion inlet and the ion outlet thereof, and a set of ion gates each controllable between an open position to pass ions therethrough and a closed position to block ions from passing therethrough. The set of ion gates may be controlled to pass at least some ions traveling through the single-pass drift tube into the multiple-pass drift tube via the ion inlet of the multiple-pass drift tube and to pass at least some ions traveling through the multiple-pass drift tube into the single-pass drift tube via the ion outlet of the multiple-pass drift tube.