Electrostatic Linear Ion Trap 2D Fourier Transform Mass Spectrometry
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Solution Overview
Problem
Conventional mass spectrometry techniques, such as 2D FT-ICR MS and quadrupole LIT, require complex encoding pulses to correlate precursor and product ions, leading to high costs and limited resolution, especially in analyzing complex samples like crude oil or blood.
Innovation Solution
The use of an electrostatic linear ion trap (ELIT) for 2D Fourier transform mass spectrometry, which simplifies the process by employing only excitation and fragmentation pulses, eliminating the need for encoding pulses and allowing simultaneous measurement of precursor and product ion data without precursor ion isolation, thereby reducing complexity and increasing resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional 2D FT-ICR MS or quadrupole LIT techniques are used to perform 2D FT MS, then precursor and product ion data can be correlated, but complex encoding pulses are required which increase device complexity and cost
Solution Approach 1:
The patent extracts and eliminates the complex encoding pulse component from the traditional 2D FT MS pulse sequence. By using only excitation and fragmentation pulses in the ELIT, the system achieves 2D FT MS functionality without requiring the encoding pulses that complicate conventional FT-ICR MS and quadrupole LIT systems
Solution Approach 2:
The ELIT system uses the natural axial oscillation of ions between reflectrons to provide the frequency encoding function that traditionally required external encoding pulses. The ion oscillation itself serves the encoding purpose, eliminating the need for separate encoding pulse generation and application
2Measurement precision
If FT-ICR MS is used to perform 2D FT MS, then high mass resolution can be achieved, but the system becomes expensive and less portable
Solution Approach 1:
The patent replaces the complex magnetic field system of FT-ICR MS with an electrostatic field-based ELIT system. By using electrostatic reflectrons instead of superconducting magnets and RF encoding pulses, the system achieves comparable mass resolution while being more compact, less expensive, and more portable
Solution Approach 2:
The patent changes the fundamental operating parameters from magnetic field-based cyclotron resonance to electrostatic field-based axial oscillation. This parameter change enables the system to achieve high mass resolution through electrostatic confinement and detection of image currents, eliminating the need for expensive magnetic infrastructure
3Measurement precision
If conventional tandem mass spectrometry with precursor ion isolation is used, then product ion analysis can be performed, but the analysis time increases linearly with the number of ions
Solution Approach 1:
The patent enables continuous simultaneous analysis of all precursor ions in the trap by eliminating the sequential isolation step. All ions undergo fragmentation and detection in parallel, making the analysis process continuous rather than sequential, which dramatically increases productivity for complex mixtures
Solution Approach 2:
The patent transitions from one-dimensional sequential precursor isolation to two-dimensional simultaneous analysis by using the time domain to encode precursor ion identities. The frequency of axial oscillation serves as the encoding dimension, allowing parallel measurement of multiple precursors and their products without temporal separation
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 efficient, cost-effective 2D FT MS with improved mass resolution and reduced complexity, capable of analyzing complex mixtures without the need for precursor ion isolation, and allows for faster analysis times with a more compact and portable mass analyzer.
Implementation Method 1
an electrostatic linear ion trap (ELIT) for 2D Fourier transform mass spectrometry
Implementation Method 2
ions are injected into the ELIT and are caused to oscillate axially between two electric fields produced by two sets of reflectrons
Implementation Method 3
perform position-dependent fragmentation of the oscillating ions within T acq1 at one or both turning points of the oscillating ions adding product ions to the oscillating ions
Implementation Method 4
measure a time domain image current of the oscillating ions from ion injection to a total acquisition time, T acq1
Data Source
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AI summary
A mass spectrometer is operated to simultaneously measure precursor and product ion data over a number of acquisitions. For each acquisition, the following steps are performed. Ion transfer optics inject ions from an ion beam into an ELIT causing the ions to oscillate axially between two electric fields produced by two the sets of reflectrons. The ELIT measures a time domain image current of the oscillating ions from ion injection to a total acquisition time, Tacq1, and fragments the oscillating ions at one or both turning points of the oscillating ions adding product ions to the oscillating ions. The fragmentation is performed at a delay time relative to the ion injection that is increased by a time increment in each subsequent acquisition making the fragmentation dependent on ion position. The measured time domain image current is stored as a row or column of a two-dimensional matrix.