Mass Spectrometer Ionization Chamber Pressure Control
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Solution Overview
Problem
Existing mass spectrometry methods face issues with sample ionization leading to fragmentation, reduced sensitivity, and low throughput due to complex sample introduction systems and ion loss during transfer to the mass analyzer.
Innovation Solution
A mass spectrometer configuration with a sample attaching member, an ionizing chamber, and a vacuum chamber, featuring an opening/closing mechanism to control pressure, allowing for sample ionization within the ionization source under controlled conditions to minimize fragmentation and enhance sensitivity, using a resistance heating filament and dielectric barrier discharge for soft ionization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a probe is introduced from atmosphere to sample vaporizing chamber, then sample introduction is achieved, but device complexity increases due to need for preparatory exhaust chamber
Solution Approach 1:
The invention combines the sample vaporizing chamber and ionization source into a single integrated chamber. The probe is introduced directly into the ionization source chamber where sample vaporization and ionization occur simultaneously, eliminating the need for separate preparatory exhaust chambers and transfer lines, thus simplifying the overall device structure.
Solution Approach 2:
The invention extracts and eliminates the preparatory exhaust chamber from the traditional mass spectrometer configuration. By performing both sample vaporization and ionization in the same chamber as the mass analyzer, the unnecessary intermediate chamber is removed, reducing device complexity.
2Reliability
If sample gas moves from sample vaporizing chamber to ionization source, then ionization is achieved, but sensitivity deteriorates due to ion loss in transfer line
Solution Approach 1:
The invention merges the sample vaporization process and ionization process into a single spatial location (the ionization source chamber). Sample vaporization occurs directly within the ionization source, and ionization occurs immediately at the same location, completely eliminating the transfer line where ion loss previously occurred, thus maintaining high sensitivity.
3Reliability
If high energy electrons impact sample for EI ionization, then ionization is achieved, but sample fragmentation occurs complicating mass spectrum
Solution Approach 1:
The invention changes the ionization parameter from high energy electron impact (EI) to low energy ion-molecule reactions (chemical ionization). By using reagent ions with lower kinetic energy and relying on chemical reaction mechanisms rather than direct impact, the ionization efficiency is maintained while sample fragmentation is significantly reduced, producing cleaner mass spectra.
4Temperature
If probe is introduced into vacuum chamber, then sample vaporization is achieved, but highly volatile samples vaporize at wrong time point
Solution Approach 1:
The invention introduces the probe into the ionization source chamber before the vacuum is fully established. The probe is positioned in place beforehand, and only after the chamber is properly evacuated does the sample vaporization and ionization process begin. This preliminary positioning prevents premature vaporization of highly volatile samples and ensures proper measurement timing.
5Reliability
If ions are conveyed through small orifice from atmospheric pressure, then mass analysis is achieved, but ion loss occurs reducing sensitivity
Solution Approach 1:
The invention extracts and eliminates the small orifice from the ion transfer path. By performing ionization within the vacuum chamber and using a larger aperture for ion introduction, the restrictive orifice that caused significant ion loss is removed, thereby maintaining high sensitivity while still enabling mass analysis.
6Temperature
If heated gas is blown to vaporize sample, then gasification is achieved, but sample gas diffusion occurs reducing ionization efficiency
Solution Approach 1:
The invention uses a controlled gas flow system to vaporize the sample. Instead of blowing heated gas directly onto the sample which causes diffusion, a gentle carrier gas flow is used to transport the vaporized sample molecules in a directed manner toward the ionization region, maintaining sample gas concentration and preventing diffusion losses.
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 configuration achieves high sensitivity and throughput by reducing ion fragmentation and sample loss, allowing for efficient ion transport to the mass analyzer with minimal diffusion and adsorption, while simplifying the sample introduction process and enabling downsizing of the instrument.
Implementation Method 1
a resistance heating filament 100... The sample 7 is heated by heating the resistance heating filament 100
Implementation Method 2
The sample 7 is heated by heating the resistance heating filament 100... and the sample gas is ionized
Implementation Method 3
a dielectric substance 20... a discharge produced plasma 10 is generated... the sample gas is ionized by ion-molecule interaction of the water cluster ions
Implementation Method 4
a discharge produced plasma 10 is generated... the sample gas is ionized
Implementation Method 5
a vacuum pump 2... a vacuumed chamber 3 a pressure of which is maintained to be equal to or lower than 0.1 Pa by the vacuum pump 2
Implementation Method 6
a mass analyzer 11 of analyze the sample ions 8 introduced into the vacuumed chamber 3... ions are isolated for respective m/z
Data Source
AI summary
A mass spectrometer including a sample attaching member of attaching a sample, an ionizing chamber including an introductory port of the sample attaching member and an ionization source of generating a sample ion, a vacuumed chamber having a mass analyzer of analyzing the sample ion, and an opening/closing mechanism provided between the ionizing chamber and the vacuumed chamber, in which the opening/closing mechanism is controlled from a closed state to an open state after introducing the sample attaching member into the ionizing chamber to thereby enable to perform ionization with inconsiderable fragmentation at a high sensitivity with a high throughput.