Ion Mobility Spectrometer Drift Tube Segmentation
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Solution Overview
Problem
Ion mobility spectrometers face challenges in effectively controlling electric fields to separate ions based on their mobility, leading to inefficiencies in ion separation and analysis.
Innovation Solution
The implementation of a drift tube partitioned into cascaded segments with ion elimination regions and controlled by a system of electric field activation sources, allowing for precise manipulation of electric fields to filter ions of specific mobilities through sequential activation and deactivation, enabling the separation of ions with predefined ion mobility or range of mobilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a drift tube is partitioned into cascaded segments with ion elimination regions, then ion separation precision is improved, but device complexity increases
Solution Approach 1:
The drift tube is divided into multiple cascaded drift tube segments, each with its own ion elimination region. This segmentation allows for staged ion separation where ions are progressively filtered by mobility across multiple sections, enhancing resolution while managing complexity through modular design
Solution Approach 2:
Ion elimination regions are positioned between drift tube segments to pre-filter ions before they enter subsequent segments. This preliminary action removes unwanted ion populations early in the process, improving the precision of final ion separation while reducing the burden on later stages
2Measurement precision
If electric field activation sources are sequentially activated to filter ions by mobility, then ion mobility resolution is improved, but energy consumption increases
Solution Approach 1:
Electric field activation sources are sequentially and periodically activated in a cyclic manner, where each source is turned on for a specific duration to filter ions of particular mobilities. This periodic activation pattern enables high-resolution ion mobility separation while managing energy consumption through controlled duty cycles
Solution Approach 2:
The system pre-activates specific electric field sources based on anticipated ion mobility ranges, filtering ions before they reach detection regions. This preliminary filtering action improves resolution by preparing ion populations in advance, while energy is consumed only when and where needed
3Measurement precision
If ions are allowed to travel around the drift tube multiple times, then analysis sensitivity is improved, but analysis time increases
Solution Approach 1:
Ions are maintained in continuous circulation around the closed drift tube path, repeatedly passing through separation and detection regions. This continuous action allows multiple measurements of the same ion population without interruption, enhancing sensitivity through signal accumulation while the closed-loop design maintains efficient ion trajectories
Solution Approach 2:
The system employs periodic ion gate signals that open at specific intervals to allow ions to exit to the detector after completing predetermined numbers of revolutions. This periodic sampling enables sensitive detection of ions that have circulated multiple times, balancing enhanced sensitivity with controlled analysis time
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 the selective transmission of ions with specific mobilities, enhancing the resolution and sensitivity of ion mobility spectrometry by filtering out ions that do not match the defined mobility, thereby improving the accuracy of ion analysis.
Implementation Method 1
A number, M, of electric field activation sources may each be operatively connected to one or more of the plurality of drift tube segments such that, when activated, each establishes a repulsive electric field in at least one of the first M ion elimination regions and in every following Mth ion elimination region, and establishes an electric drift field in all remaining ion elimination regions and in all of the plurality of cascaded drift tube segments
Implementation Method 2
Ion mobility spectrometers are analytical instruments that are used to separate ions in time as a function of ion mobility
Data Source
AI summary
An ion mobility spectrometer instrument has a drift tube that is partitioned into a plurality of cascaded drift tube segments. A number of electric field activation sources may each be coupled to one or more of the plurality of drift tube segments. A control circuit is configured to control operation of the number of electric field activation sources in a manner that sequentially applies electric fields to the drift tube segments to allow only ions having a predefined ion mobility or range of ion mobilities to travel through the drift tube. The drift tube segments may define a linear drift tube or a closed drift tube with a continuous ion travel path. Techniques are disclosed for operating the ion mobility spectrometer to produce highly resolved ion mobility spectra.