FAIMS Compensation Voltage Sweeps for Multi-Fraction Ion Collection
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Solution Overview
Problem
Field asymmetric-waveform ion-mobility spectrometry (FAIMS) devices typically limit ion species identification by only transmitting ions at specific compensation voltage (CV) settings, resulting in fewer identified ion species in a single experiment compared to mass spectrometers without FAIMS, as ions not transmitting at the set CV are lost and cannot be identified.
Innovation Solution
A system and method that dynamically vary the compensation voltage (CV) applied to the FAIMS electrode during the opening period of the injection gate, allowing multiple CV fractions to be transmitted and analyzed collectively in a single scan, using time-varying voltage waveforms such as ramp, triangle, or sawtooth patterns, to increase the number of ion species identified.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single compensation voltage setting is applied to the FAIMS device, then the signal-to-noise ratio is enhanced for specific ion species, but the number of identified ion species decreases
Solution Approach 1:
The patent applies a dynamically varying compensation voltage during the ion transmission period instead of a static voltage. The voltage is modulated at a frequency that matches the ion mobility separation timescale, allowing the FAIMS device to transmit multiple ion species with different mobilities sequentially, thereby increasing the number of identified ions while maintaining signal quality
Solution Approach 2:
The compensation voltage is applied in periodic cycles, alternating between different voltage values that correspond to different ion mobility ranges. This periodic modulation allows repeated transmission opportunities for various ion species, improving both the quantity of identified ions and the consistency of signal-to-noise enhancement
2Adaptability or versatility
If multiple compensation voltage settings are applied sequentially, then the number of identified ion species increases, but the analysis time increases
Solution Approach 1:
The patent implements continuous voltage modulation throughout the entire ion transmission window rather than switching between discrete voltage settings. This continuous action ensures that ions across a broad mobility range are transmitted without interruption, achieving high ion species identification in a single continuous scan without the time penalty of sequential measurements
Solution Approach 2:
The patent transforms the traditional single-dimension approach (one voltage setting per scan) into a two-dimensional approach by introducing time as an additional dimension for voltage variation. The compensation voltage becomes a function of both magnitude and time, allowing simultaneous optimization for multiple ion species within a single mass spectrometer scan cycle
3Device complexity
If a static compensation voltage is applied, then the FAIMS device structure is simple, but ions not transmitting at the set CV are lost and cannot be identified
Solution Approach 1:
The patent dynamically changes the compensation voltage parameter during ion transmission, sweeping through a range of voltage values that correspond to different ion mobility ranges. This parameter variation ensures that ions with different mobilities are sequentially transmitted to the detector, preventing ion loss while maintaining the simplicity of the FAIMS device structure
Solution Approach 2:
The FAIMS device is configured to perform multiple functions within a single operation: it can transmit ions across a broad mobility range, maintain signal-to-noise enhancement, and identify multiple ion species simultaneously. The dynamic voltage modulation enables the device to adapt to different ion types without requiring structural modifications or multiple specialized components
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 enhances ion species identification by transmitting and analyzing adjacent CV fractions in a single scan, increasing the number of identified ions and improving the coverage of ion species across the entire CV range, thereby improving the efficiency of mass spectrometry analysis.
Implementation Method 1
Field asymmetric-waveform ion-mobility spectrometry (FAIMS) device can be used in conjunction with a mass spectrometer to transmit a different gas phase ion population into the mass spectrometer at each compensation voltage (CV) setting
Implementation Method 2
controller circuit configured to open the injection gate and apply a dynamic compensation voltage to an electrode of the FAIMS device while the injection gate is open
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
A system for collecting multiple compensation voltage fractions includes a field asymmetric-waveform ion-mobility spectrometry (FAIMS) device which receives ions generated from a sample, such as a biological sample. A mass spectrometer injection gate is configured to inject, when in an open state, ions transmitted by the FAIMS device into a mass analyzer of the mass spectrometer. A controller circuit is configured to open the injection gate and apply a dynamic compensation voltage (CV) to an electrode of the FAIMS device while the injection gate is open. The dynamic CV can have a waveform in the shape of a ramp, triangle, wavelet, sinusoid, or another shape. The dynamic CV includes CVs associated with multiple adjacent CV fractions, and the FAIMS device is configured to transmit the multiple adjacent CV fractions into the mass analyzer via the open injection gate to be scanned together by the mass analyzer in a single experiment.