Differential Ion Mobility Trapping for Hybrid Mass Separation
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Solution Overview
Problem
Current trapped ion mobility spectrometry techniques face limitations in effectively separating and analyzing all ion species, particularly at high electric field strengths, leading to the loss of non-transmitted components during FAIMS, and lack an additional dimension of separation in hybrid mass spectrometric systems.
Innovation Solution
A differential trapped ion mobility separator (dTIMS) is introduced, utilizing alternating axial electric fields with varying strengths to trap and separate ions based on their differential mobility, allowing for the analysis of all introduced ion species and enhancing the capabilities of hybrid mass spectrometric systems by adding a new dimension of separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FAIMS technique is used to separate ions based on differential mobility at high electric field strength, then selected ion components can be transmitted, but all other ion components are filtered out and lost
Solution Approach 1:
The patent segments the ion analysis process into multiple sequential stages: first separating ions by differential mobility using asymmetric electric fields, then further separating transmitted ions by mobility using symmetric electric fields. This segmentation allows different ion components to be analyzed in different stages rather than losing them in a single filtering step.
Solution Approach 2:
The patent adds a second separation dimension by introducing symmetric electric fields that act perpendicular to the asymmetric field direction. This creates a two-dimensional separation space where ions are first separated by differential mobility (asymmetric field) and then by mobility (symmetric field), allowing comprehensive analysis of all ion species rather than just transmitting selected ones.
2Adaptability or versatility
If conventional trapped ion mobility spectrometry is used, then ions can be separated according to mobility, but it lacks an additional dimension of separation in hybrid mass spectrometric systems
Solution Approach 1:
The patent merges two types of ion mobility separation techniques (differential mobility separation using asymmetric fields and mobility separation using symmetric fields) into a single hybrid device. This combination provides an additional dimension of separation capability while integrating both functions within one instrument structure, enhancing versatility without requiring completely separate systems.
Solution Approach 2:
The patent designs the ion mobility separator to perform multiple functions: it can separate ions by differential mobility using asymmetric electric fields, separate ions by mobility using symmetric electric fields, and operate in various modes (transmission mode, filtering mode, analysis mode). This multi-functionality provides an additional separation dimension while maintaining a unified device architecture.
3Speed
If high electric field strength is applied in trapped ion mobility spectrometry, then ion drift velocity increases, but mobility becomes dependent on applied field with considerable non-linear dependence
Solution Approach 1:
The patent employs asymmetric electric field waveforms where the positive voltage amplitude differs from the negative voltage amplitude. This asymmetry allows the system to operate at high field strengths to achieve fast ion drift velocities while the asymmetric waveform design compensates for non-linear mobility effects, enabling accurate differential mobility measurements despite the non-linear relationship between field strength and mobility.
Solution Approach 2:
The patent uses periodic alternating electric fields with asymmetric waveforms to drive ion separation. The periodic application of asymmetric fields allows ions to experience controlled acceleration and deceleration cycles, enabling accurate measurement of differential mobility through the periodic modulation effect while maintaining high average drift velocities for efficient analysis.
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
The dTIMS enables the trapping and separation of all ion species according to their differential mobility, improving the analysis capabilities of hybrid mass spectrometric systems by allowing for the selection and discrimination of ions based on charge state, thereby increasing peak capacity and reducing spectral crowding.
Implementation Method 1
the first axial force has an effect on the movement of the ions that is dependent on differential mobility by virtue of its interplay with said gas
Implementation Method 2
a first generator that causes a first axial force to be exerted on the ions along said axis by applying separating voltages to said first electrode and said second electrode to generate an alternating axial electric field
Implementation Method 3
said first generator and said second generator are configured such that at least one of the axial forces is changing in strength along the axis for trapping ions along said axis at mobility dependent positions where a force equilibrium of said first axial force and said second axial force exists for the ions
Data Source
AI summary
The invention relates to a trapped ion mobility separator, a hybrid mass spectrometric system and a method for analyzing ions. The trapped ion mobility separator comprises an ion channel in which ions move along an axis between a first end, at which ions are introduced into said ion channel, and a second end. Two axial forces acting on the ions are provided, the first axial force being caused by an alternating axial electric field and having an effect on the movement of the ions that is dependent on differential mobility, and the second axial force counteracting the first axial force at least temporarily. At least one of the two forces varies spatially and temporally, so that ions are trapped along the axis at mobility dependent positions and are driven progressively to one end of the ion channel as a function of their differential mobility.