FAIMS Ion Filtering for Mass Spectrometer Duty Cycle Improvement
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Solution Overview
Problem
Current mass spectrometers face reduced duty cycles due to the limited storage capacity of storage traps being quickly filled by singly-charged ions, which reduces the number of analytically significant multiply-charged ions available for analysis, particularly in bottom-up proteomics experiments.
Innovation Solution
Implementing ion mobility separation, specifically using a field asymmetric-waveform ion-mobility spectrometry (FAIMS) device to filter out singly-charged ions and preferentially transmit multiply-charged ions, combined with an ion accumulator and storage trap to manage ion flow based on the mass analyzer's availability for analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the storage trap accepts all ions from the ion source, then the storage trap reaches capacity quickly, but the duty cycle decreases and multiply-charged ions are wasted
Solution Approach 1:
The ion mobility separator extracts and removes singly-charged ions from the ion stream before ions enter the storage trap. By taking out the harmful singly-charged ions that quickly fill the storage trap, the system allows multiply-charged ions to be stored and analyzed without the storage trap reaching capacity prematurely, thereby improving the duty cycle while maintaining adequate ion storage quantities
Solution Approach 2:
The ion mobility separator acts as an intermediary device between the ion source and the storage trap. It selectively transmits multiply-charged ions while blocking singly-charged ions, serving as a filtering mediator that optimizes the composition of ions entering the storage trap. This intermediary function ensures that the storage trap receives primarily multiply-charged ions, improving both the duty cycle and the quality of ions available for analysis
2Quantity of substance
If the storage trap capacity is increased, then more ions can be stored, but the device complexity increases
Solution Approach 1:
Rather than increasing the storage trap capacity to handle all ions, the system extracts singly-charged ions before they enter the storage trap. This approach maintains the original storage trap capacity while effectively increasing the number of useful multiply-charged ions that can be stored, avoiding the complexity and cost associated with enlarging the storage trap
Solution Approach 2:
The ion mobility separator serves as an intermediary filtering device that simplifies the overall system architecture compared to increasing storage capacity. By placing a relatively simple ion mobility separation stage before the storage trap, the system achieves better ion storage efficiency without the complex engineering required to design and implement a larger storage trap
3Productivity
If ion mobility separation is implemented, then multiply-charged ion transmission is improved, but the device complexity increases
Solution Approach 1:
The ion mobility separator operates continuously to separate singly-charged ions from multiply-charged ions throughout the ion beam generation process. This continuous separation ensures that multiply-charged ions are consistently transmitted to the storage trap without interruption, maximizing the duty cycle improvement while using a compact device that does not significantly add to system complexity
Solution Approach 2:
The ion mobility separator uses electrical fields and ion mobility differences rather than mechanical filtration or separation mechanisms. This non-mechanical approach to ion separation avoids the complexity of moving parts and mechanical systems, achieving effective ion separation through electromagnetic fields while keeping the device relatively simple and maintenance-free
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 significantly increases the duty cycle of the mass spectrometer by allowing more multiply-charged ions to be analyzed, improving data quality and efficiency by reducing the waste of ions and optimizing ion storage and transmission.
Implementation Method 1
a field asymmetric-waveform ion-mobility spectrometry (FAIMS) device configured to receive the singly-charged ions and the multiply-charged ions, and preferentially transmit multiply-charged ions
Implementation Method 2
an ion accumulator arranged to receive and confine the ions transmitted by the FAIMS device
Implementation Method 3
a storage trap configured to receive the ions released from the ion accumulator and store the released ions
Implementation Method 4
an electrospray ionization (ESI) source configured to receive a component separated from the biological sample and generate singly-charged ions and multiply-charged ions from the component
Data Source
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AI summary
Using ion mobility separation to improve a duty cycle of a mass spectrometer is described. In one aspect, a mass spectrometer can use an ion-mobility spectrometer to allow for more multiply-charged ions to transmit through than singly-charged ions. This results in a mass analyzer to perform a mass analysis with more multiply-charged ions.