AP-ECD Mass Spectrometry for Parent-Fragment Ion Association
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Solution Overview
Problem
Existing atmospheric pressure Electron Capture Dissociation (AP-ECD) mass spectrometers face challenges in associating parent ions with their fragment ions due to the high-pressure environment, leading to complex spectra and limited analytical utility, especially when analyzing mixtures.
Innovation Solution
The method involves performing ECD and/or ETD reactions at atmospheric pressure, using an RF ion guide or ion trap to interact electrons or reagent anions with parent ions, and continuously associating fragment ions with their parent ions through simultaneous mass analysis, leveraging liquid chromatography or ion mobility separation to correlate elution or drift times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ion selection techniques are used in high pressure region, then parent ions can be selected for fragmentation, but the high pressure environment prevents effective ion selection and association
Solution Approach 1:
The invention segments the mass spectrometer into distinct pressure regions: a high pressure ion source region for ECD/ETD fragmentation and a low pressure analysis region for ion selection and detection. This spatial segmentation allows each region to operate under optimal conditions without interfering with the other, resolving the contradiction between maintaining high pressure for fragmentation and low pressure for precise ion selection.
Solution Approach 2:
The invention introduces an intermediary transfer region with pressure reduction mechanisms (such as skimmers or capillaries) that mediates the transition of ions from the high pressure fragmentation region to the low pressure analysis region. This intermediary structure allows ions to be transferred while maintaining the pressure differential, enabling both high pressure fragmentation and low pressure ion selection to coexist.
2Ease of operation
If single parent ion selection is used, then parent-ion/fragment-ion association is simple, but duty cycle is low as other parent ions are discarded
Solution Approach 1:
The invention enables continuous useful action by allowing simultaneous fragmentation and analysis of multiple parent ions in parallel. The high pressure region continuously fragments all incoming parent ions via ECD/ETD, while the low pressure region continuously analyzes and selects specific ions. This continuous parallel processing eliminates the duty cycle losses inherent in sequential single-ion selection methods.
Solution Approach 2:
The invention adds the dimension of pressure as a separating variable, allowing ions to be processed in three dimensions: mass-to-charge ratio (m/z), time, and pressure. By utilizing pressure differential as an additional dimension, the system can simultaneously perform fragmentation at high pressure and selective analysis at low pressure, effectively multiplying the analytical capacity beyond what single-pressure systems can achieve.
3Adaptability or versatility
If AP-ECD is used for mixture analysis, then comprehensive fragmentation occurs, but spectra become complex with multiple ion types making association difficult
Solution Approach 1:
The invention extracts specific ion types from the complex mixture by utilizing mass-selected ion transmission through the pressure differential system. The low pressure region allows for selective transmission of fragment ions while excluding other ion types (such as solvent ions, dopant ions, and unreacted parent ions) through precise mass filtering and mobility separation, effectively extracting the desired fragment ion information from the complex spectral mixture.
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 enables effective fragmentation and association of parent ions with their fragment ions, simplifying data processing and improving the analytical utility of AP-ECD mass spectrometry by correlating ions based on their elution or drift times, enhancing the identification of biomolecules and disulphide linked species.
Implementation Method 1
a method of mass spectrometry comprising: (i) causing a beam of electrons or reagent anions to interact with parent ions within an RF ion guide or ion trap so as to fragment the parent ions
Implementation Method 2
causing a beam of electrons or reagent anions to interact with parent ions within an RF ion guide or ion trap so as to fragment the parent ions
Implementation Method 3
a mass analysing device arranged and adapted to mass analyse the parent ions and the fragment or product ions
Implementation Method 4
leveraging liquid chromatography or ion mobility separation to correlate elution or drift times
Implementation Method 5
leveraging liquid chromatography or ion mobility separation to correlate elution or drift times
Data Source
Figure 1~2
AI summary
A method of mass spectrometry and a mass spectrometer performing mass analysing parent ions; subjecting parent ions to ECD and/or ETD thereby producing fragment ions and mass analysing the resulting fragment ions; subjecting parent ions to ECD and/or ETD thereby producing intermediate ions, which are non-dissociated parent ions held together by covalent interactions and/or charge reduced parent ions, and subjecting these intermediate ions to a fragmentation technique other than ETC and/or ECD thereby producing fragment ions and analysing the resulting fragment ions; and associating parent ions with fragment ions.