Time-of-Flight Mass Spectrometer Polygonal Extraction Field
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Solution Overview
Problem
Conventional delayed extraction methods in time-of-flight mass spectrometers, such as MALDI ion sources, face limitations in achieving high mass resolution over a wide mass/charge ratio range due to insufficient correction of initial energy fluctuations in ions, leading to restricted mass resolution improvements.
Innovation Solution
A time-of-flight mass spectrometer design incorporating an extraction electrode, auxiliary electrodes, and a voltage generator to form an electric field with a polygonal potential gradient, allowing for controlled acceleration of ions based on their mass/charge ratio, thereby enhancing energy convergence and mass resolution across a broader range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional delayed extraction method is used, then ion extraction is simplified, but mass resolution is limited due to insufficient correction of initial energy fluctuations
Solution Approach 1:
The extraction electrode system is segmented into multiple electrodes (first extraction electrode, second extraction electrode, and auxiliary electrodes) positioned at different locations. Each electrode can be independently controlled to create a complex polygonal potential gradient that cannot be achieved with a single electrode, thereby improving mass resolution through better energy correction.
Solution Approach 2:
Different regions of the extraction space are assigned different potential gradients by applying specific voltages to different electrodes. The auxiliary electrodes create localized field modifications in specific regions to correct energy fluctuations of ions with different mass-to-charge ratios, achieving uniform mass resolution across the entire mass range.
2Measurement precision
If simple extraction electric field is used, then device structure is simple, but energy convergence of ions is insufficient
Solution Approach 1:
The extraction electric field is made dynamic by independently controlling the voltages applied to multiple electrodes. The polygonal potential gradient can be adjusted in real-time to optimize energy convergence for different mass-to-charge ratio ranges, allowing the system to adapt to different measurement requirements.
Solution Approach 2:
Auxiliary electrodes serve as intermediary elements between the main extraction electrodes. These intermediate electrodes create additional potential gradient segments that refine the energy distribution of ions, acting as mediators to achieve better energy convergence without requiring complete redesign of the main extraction system.
3Measurement precision
If uniform acceleration is applied to all ions, then extraction process is simple, but initial energy fluctuations are not corrected
Solution Approach 1:
The voltage parameters applied to different extraction electrodes are independently optimized to create a polygonal potential gradient. By changing the voltage parameters of auxiliary electrodes relative to the main extraction electrodes, the system creates non-uniform acceleration fields that compensate for initial energy fluctuations of ions with different mass-to-charge ratios.
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
The new design effectively corrects initial energy fluctuations and provides appropriate acceleration energy to ions across a wide mass/charge ratio range, significantly improving mass resolution beyond conventional methods.
Implementation Method 1
a voltage generator for applying prescribed voltages to the sample holding part, the auxiliary electrode, and the extraction electrode to form an electric field for extracting and accelerating ions from the sample surface
Implementation Method 2
When this sample is irradiated with a laser beam, the matrix absorbs the energy of the laser beam and converts the energy into thermal energy
Implementation Method 3
A matrix assisted laser desorption/ionization (MALDI) ion source based on the MALDI method is widely used as a TOFMS ion source
Implementation Method 4
separates various ions by each mass/charge ratio m/z in accordance with the time of flight until the ions reach a detector
Data Source
AI summary
A time-of-flight type mass spectrometer in which, at the time when ions are generated by irradiating a sample with a laser beam, an extraction electric field having a potential gradient that decreases gradually from a sample plate toward an extraction electrode is formed. Ions are roughly separated in accordance with the m/z in the extraction region due to the effect of this electric field, and ions with a large m/z remain near the sample. The voltages applied to the sample plate and an auxiliary electrode are increased after a delay time has passed so as to form an acceleration electric field having a potential gradient with a polygonal line pattern. Since this electric field is similar to an ideal potential gradient curve, it is possible to provide the ions with appropriate potential energy changes for each m/z, improving resolution by appropriately realizing energy convergence over a wide m/z range.