Multi-compartment Collision Cell for Tandem Mass Spectrometry
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Solution Overview
Problem
Tandem mass spectrometry techniques face challenges in achieving high-performance analysis of fragments due to limited time for fragment scans, incompatibility with slow fragmentation methods, and low transmission in traditional multi-channel MS/MS methods, which results in poor precursor isolation and dynamic range limitations.
Innovation Solution
A method and apparatus that involve a multi-compartmental fragmentation cell where precursor ions are converted into a time-separated sequence, allowing for parallel fragmentation and accumulation, with each ion species allocated to a dedicated chamber for optimal fragmentation conditions, enabling high-resolution analysis and sufficient time for slow fragmentation techniques like electron-transfer dissociation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional multi-channel MS/MS methods are used to select precursors in parallel, then precursor selection throughput is improved, but fragment analysis performance deteriorates due to low transmission and insufficient scan time
Solution Approach 1:
The system segments the precursor selection and fragment analysis processes into separate spatial and temporal domains. Multiple precursors are selected in parallel across different spatial channels, then sequentially transferred to a single high-performance fragment analysis region. This segmentation allows independent optimization of each function: parallel selection throughput and sequential analysis precision.
Solution Approach 2:
The invention transitions from simultaneous spatial parallelism to temporal sequential processing with enhanced performance. By adding the time dimension to the analysis process, the system achieves high-resolution fragment scans that were previously impossible in parallel multi-channel configurations, while maintaining overall throughput through coordinated temporal sequencing.
2Measurement precision
If scan time for fragment analysis is increased to improve signal-to-noise ratio, then measurement precision is improved, but precursor isolation performance deteriorates due to time constraints
Solution Approach 1:
The system performs preliminary precursor selection and isolation in parallel channels before the fragment analysis phase. By completing precursor isolation beforehand, the subsequent fragment analysis can utilize the full allocated scan time without compromising precursor selection efficiency, achieving both high signal-to-noise ratio and adequate isolation performance.
Solution Approach 2:
While one precursor packet undergoes high-resolution fragment analysis, other precursor packets continue to be selected and prepared in parallel channels. This continuous operation ensures that the extended scan time for high-quality fragment analysis does not reduce overall system throughput, as the parallel channels maintain productive activity throughout.
3Productivity
If parallel mass analysers are used to select multiple precursors simultaneously, then productivity is improved, but device complexity increases due to multiple detectors and channels
Solution Approach 1:
The system merges multiple parallel precursor selection channels into a single fragment analysis mass analyser. Instead of requiring one mass analyser per precursor channel, the invention combines the analysis function into one instrument that sequentially processes precursors from different selection channels, significantly reducing the number of detectors and analysers needed while maintaining parallel selection capability.
Solution Approach 2:
The single mass analyser is designed to serve multiple functions: it analyzes fragments from different precursor packets sequentially, handles multiple mass ranges, and works with various fragmentation techniques. This multi-functional design replaces the need for multiple specialized analysers, reducing system complexity while preserving analytical versatility.
4Productivity
If fast fragmentation is used to maintain nested times approach, then productivity is maintained, but adaptability deteriorates by excluding slow fragmentation methods like ETD
Solution Approach 1:
The system dynamically adapts the fragmentation timing to match the requirements of different fragmentation techniques. For fast fragmentation methods, the system operates in rapid nested times mode. For slow methods like ETD, the system extends the fragmentation duration while maintaining precursor isolation through continued parallel channel operation, allowing versatile technique selection without compromising throughput.
Solution Approach 2:
The system changes operational parameters including fragmentation time, collision energy, and electron transfer conditions based on the selected fragmentation technique. This parameter adaptability allows the same hardware platform to support both fast and slow fragmentation methods, achieving versatility without sacrificing the productivity benefits of the nested times architecture.
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 high-resolution analysis of fragments and sufficient time for slow fragmentation methods, enhancing analytical performance and throughput while maintaining sensitivity, and is compatible with various fragmentation techniques.
Implementation Method 1
ion beam splitting can be achieved through the use of a pulsed ion mobility spectrometer
Implementation Method 2
through a linear time-of-flight mass spectrometer as is shown in U.S. Pat. No. 5,206,508, or using multi-reflecting time-of-flight mass spectrometer
Implementation Method 3
this first stage of mass analysis is followed by fast fragmentation, typically in a collision cell (preferably having an axial gradient) or by a pulsed laser
Implementation Method 4
a rastering device that directs incident ions into a chosen one of multiple fragmentation cell chambers
Data Source
AI summary
A method and apparatus for tandem mass spectrometry is disclosed. Precursor ions are fragmented and the fragments are accumulated in parallel, by converting an incoming stream of ions from an ion source (10) into a time separated sequence of multiple precursor ions which are then assigned to their own particular channel of a multi compartment collision cell (40). In this manner, precursor ion species, being allocated to their own dedicated fragmentation cell chambers (41, 42 . . . 43) within the fragmentation cell (40), can then be captured and fragmented by that dedicated fragmentation chamber at optimum energy and/or fragmentation conditions.