Ion Gate RF Fragmentation for Selective Ion Mobility Identification
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Solution Overview
Problem
Current ion mobility spectrometry and mass spectrometry methods face challenges in accurately identifying substances of interest, particularly in the presence of contaminants or when dealing with ions of similar geometries and masses, leading to reduced sensitivity and resolution.
Innovation Solution
The implementation of an ion gate system with a first and second electrode, where an RF voltage is applied to fragment ions as they pass through, enhancing the identification process by providing additional degrees of freedom in measurement and improving the ability to differentiate between ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ion mobility spectrometry is used to identify substances, then identification capability is provided, but sensitivity and resolution are reduced when contaminants are present or when ions have similar geometries and masses
Solution Approach 1:
The patent segments the ion identification process into multiple stages: initial ion mobility measurement, followed by selective ion modification through RF heating, and then re-measurement. This segmentation allows the system to handle complex samples by processing ions in discrete steps, improving both sensitivity and identification accuracy even when contaminants are present.
Solution Approach 2:
The patent adds a new dimension to ion analysis by introducing RF heating as an additional measurement parameter beyond standard ion mobility. This creates a two-dimensional measurement space (mobility + heating response) that enables differentiation of ions with similar geometries and masses, thereby improving sensitivity without sacrificing identification accuracy.
2Loss of information
If RF electric field is applied to fragment ions for modification, then additional measurement information is provided, but device complexity increases
Solution Approach 1:
The patent makes the existing ion mobility spectrometer multi-functional by adding RF heating capability to the same device. The RF system serves dual purposes: it can heat/fragment ions for additional measurement information, and it can selectively modify specific ion types based on their mobility characteristics. This universality reduces overall system complexity compared to having separate dedicated instruments.
Solution Approach 2:
The patent changes the physical state and energy parameters of ions by applying RF heating. This parameter change allows ions to be selectively fragmented or modified based on their mobility, providing additional measurement information without requiring fundamentally new measurement techniques or complex additional instrumentation.
3Adaptability or versatility
If measurements are performed in the presence of contaminants or difficult operating conditions, then real-world applicability is improved, but ion detection and identification capability is degraded
Solution Approach 1:
The patent implements a feedback mechanism where ions are first measured by mobility, then selected and modified by RF heating, and finally re-measured. This iterative feedback process allows the system to compensate for the presence of contaminants by selectively enhancing the signal from target ions while suppressing background interference, thereby maintaining identification capability in difficult operating conditions.
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 increases the sensitivity and selectivity of ion mobility spectrometry methods, allowing for better resolution between ions with similar mobilities and improving identification accuracy, even in challenging conditions.
Implementation Method 1
an RF voltage is applied between the first electrode and the second electrode to fragment ions passing through the region
Implementation Method 2
measuring the time it takes the resulting ions to travel a known distance under a known electric field. This is known as time of flight ion mobility spectrometry—TOFIMS
Data Source
AI summary
An ion mobility spectrometry method comprising (i) applying a voltage difference between a first electrode of an ion gate and a second electrode of the ion gate to prevent ions from leaving a reaction region of an ion mobility spectrometer; (ii) opening the ion gate to allow the ions to travel from the reaction region into a modification region between the first electrode and the second electrode; (iii) applying a radio frequency, RF, voltage between the first electrode and the second electrode to fragment the ions in the modification region to provide daughter ions; (iv) allowing the daughter ions to travel from the modification region into a drift region of the ion mobility spectrometer towards a collector; (v) closing the ion gate; and (vi) determining the time of flight of the daughter ions from the ion gate to the collector.