Linear TOF Ion Source Layout for High Mass Resolving Power
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Solution Overview
Problem
Current time-of-flight (TOF) mass spectrometers face challenges in achieving high mass resolving power (MRP) above 100,000, particularly due to limitations in ion source design and ion trajectory, which compromise between resolution and sensitivity.
Innovation Solution
A linear TOF mass spectrometer design featuring specific geometric and electric field configurations, including a sample plate, extraction plate, and end plate with optimized distances and electric fields, to achieve MRP greater than 10,000 for ions with a mass-to-charge ratio between 1,000 and 100,000, by satisfying criteria such as d1/L < 0.035 and e2/e1 ≤ 2.5.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Wiley and Mclaren type ion source with reflectron is used, then mass resolving power is improved, but ion loss occurs due to limited ion survivor time and inappropriate ion trajectory
Solution Approach 1:
The patent applies parameter changes by optimizing the extraction voltage ratio (e2/e1 ≤ 2.5) and geometric parameters (d1/L ≥ 0.035, d2/L ≥ 0.1) to achieve high mass resolving power without reflectron, thereby preventing ion loss while maintaining resolution
Solution Approach 2:
The patent extracts the reflectron component from the conventional TOF mass spectrometer design, achieving high mass resolving power through optimized ion source parameters alone, thus eliminating the ion loss problem associated with reflectron
2Measurement precision
If FT mass spectrometer is used, then higher mass resolving power is achieved, but the instrument becomes much more complicated, expensive, and difficult to operate
Solution Approach 1:
The patent creates a simplified copy of the high-resolution FT mass spectrometer functionality using a conventional TOF design with optimized parameters, achieving comparable mass resolving power without the complexity of FT instrumentation
Solution Approach 2:
By changing the extraction voltage ratio and geometric parameters of the ion source, the patent achieves high mass resolving power in a simple TOF configuration, avoiding the need for complex FT mass spectrometer architecture
3Ease of operation
If delayed extraction technique is used, then ion extraction is improved, but satisfactory improvement in mass resolving power cannot be achieved
Solution Approach 1:
The patent extends the parameter changes to include the extraction voltage ratio (e2/e1) and geometric parameters (d1/L, d2/L), which work synergistically with delayed extraction to achieve both improved ion extraction and high mass resolving power simultaneously
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 design effectively enhances the mass resolving power of TOF mass spectrometers, achieving MRP values up to 100,373 for ions with a mass-to-charge ratio of 1,000 and 114,987 for ions with a mass-to-charge ratio of 10,000, while maintaining sensitivity.
Implementation Method 1
a first electric field (e1) present between the sample plate and the extraction plate; and a second electric field (e2) present between the extraction plate and the end plate
Implementation Method 2
A TOF mass spectrometer determines the mass-to-charge (m/z) ratio of ions based on the time they fly across a certain distance
Data Source
AI summary
Provided herein are designs of a linear time-of-flight (TOF) mass spectrometer that achieves a high mass resolving power (MRP) to ions independently having a mass-to-charge (m/z) ratio between 1,000 and 100,000. The TOF mass spectrometer comprises an ion source, a flight tube, and an ion detector, in which the ion source comprises a sample plate, an extraction plate disposed at a first distance (d1) away from the sample plate; an end plate disposed at a second distance (d2) away from the extraction plate; a first electric field (e1) present between the sample plate and the extraction plate; and a second electric field (e2) present between the extraction plate and the end plate; the flight tube having a length of d3 is disposed downstream and adjacent to the ion source; and the ion detector is disposed downstream and adjacent to the flight tube; and the linear TOF mass spectrometer satisfies the set of criteria I or II, in which the set of criteria I includes (1) d1/L<0.035, in which L is the sum of d1, d2, and d3; (2) d2/L≥0.05; and (3) e2/e1≤2.5; while the set of criteria II includes, (1) d1/L≥0.035; and (2) d2/L≥0.003.