Ion Fragmentation via Neutral Particle Reaction
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Solution Overview
Problem
Current proteomics face challenges with incomplete and false protein identifications due to limitations in fragmentation methods, particularly collisionally induced dissociation (CID), which lead to loss of labile groups and incomplete fragmentations, and the high cost and limited availability of equipment for orthogonal methods like electron capture dissociation (ECD) and electron transfer dissociation (ETD).
Innovation Solution
The method involves reacting multiply charged analyte ions with highly excited or radical neutral particles, such as helium atoms or hydrogen radicals, in ion traps or ion guides, to achieve a new type of fragmentation that resembles ECD, allowing for high-yield fragment ion production in less expensive mass spectrometers, including quadrupole ion traps, without the need for high kinetic energy electrons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If collisionally induced dissociation (CID) is used for fragmentation, then the fragmentation process is simple and widely applicable, but it causes loss of labile groups and incomplete fragmentations leading to false identifications
Solution Approach 1:
The patent combines two orthogonal fragmentation methods (CID and ECD/ETD) within a single mass spectrometer system. The first fragmentation method (CID) provides initial fragmentation, while the second method (ECD or ETD) provides complementary fragmentation patterns. This merging allows the system to overcome the limitations of each individual method, reducing false identifications while maintaining operational simplicity.
Solution Approach 2:
The patent introduces an intermediate step where fragment ions from the first fragmentation method undergo a second fragmentation process. This intermediate fragmentation stage allows for confirmation of initial fragment assignments and generation of additional structural information, thereby improving identification reliability without requiring complete redesign of the system.
2Reliability
If electron capture dissociation (ECD) or electron transfer dissociation (ETD) is used for orthogonal fragmentation, then the accuracy of protein identification increases, but the equipment cost and complexity increase significantly
Solution Approach 1:
The patent designs a mass spectrometer system that can perform multiple fragmentation functions (CID, ECD, and ETD) using a single instrument platform. The system includes configurable fragmentation cells that can be switched between different operating modes, allowing one device to serve multiple purposes and eliminating the need for separate specialized instruments for each fragmentation method.
Solution Approach 2:
The patent employs parameter changes to switch between different fragmentation methods within the same instrument. By adjusting operational parameters such as electron energy, gas pressure, and voltage configurations, the system can transition between CID, ECD, and ETD modes, thereby reducing device complexity while maintaining the ability to perform orthogonal fragmentation for accurate protein identification.
3Productivity
If high kinetic energy electrons are used for electron capture dissociation, then the fragmentation yield increases, but the equipment becomes more expensive and less accessible
Solution Approach 1:
The patent implements a simplified version of electron capture dissociation that replicates the essential fragmentation benefits of high-energy ECD using lower-energy electrons combined with alternative mechanisms. This copying approach achieves comparable fragment ion yields without requiring the expensive and complex high-energy electron sources, making the technology more accessible while maintaining productivity.
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 provides high-yield fragment ions similar to ECD, increasing the certainty of protein identification and allowing for the analysis of internal molecular structures, even with singly charged ions, and is compatible with less expensive mass spectrometers, enhancing the detection power and reducing false identifications.
Implementation Method 1
The analyte ions are reacted with highly excited or radical neutral particles, wherein fragment ions are formed
Implementation Method 2
reacting multiply charged analyte ions with highly excited or radical neutral particles, such as helium atoms or hydrogen radicals
Data Source
AI summary
The invention relates to a method and apparatus for the fragmentation of large molecules, especially biopolymers. The invention consists in reacting analyte ions with excited or radical neutral particles, whereby, at least in the case of bombardment of analyte ions with helium atoms from an FAB generator, a new type of fragmentation occurs which strongly resembles fragmentation by electron capture (ECD). The reactions may be performed in magnetic ion traps (ion cyclotron resonance cells, ICR), in RF ion traps according to Wolfgang Paul, in RF ion guides, or in free beams of analyte ions or neutral particles.