Ion Source Field Balancing for Low-m/z Mass Spectrometry
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Solution Overview
Problem
Existing mass spectrometers struggle to analyze ions with low mass-to-charge ratios with high sensitivity, particularly when used without a gas chromatograph, as ions with very low mass-to-charge ratios are often lost due to bending trajectories caused by magnetic fields in the ionization chamber.
Innovation Solution
A mass spectrometer with an ion source that includes a magnetic field to guide thermal electrons helically and a deflection electric field to correct ion trajectories, ensuring efficient extraction of ions by counteracting the magnetic field's influence, especially for low mass-to-charge ratio ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a magnetic field is applied to guide thermal electrons helically and improve ionization efficiency, then ionization efficiency is enhanced, but ions with low mass-to-charge ratio experience trajectory bending and are lost
Solution Approach 1:
The patent applies preliminary anti-action by introducing a deflection electric field that counteracts the harmful effect of the magnetic field on low mass-to-charge ratio ions before they are lost. The electric field is specifically designed to deflect these ions in the opposite direction of the magnetic field's influence, preventing their trajectory bending and subsequent loss while maintaining the beneficial ionization enhancement.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the electric field parameters (voltage, timing, strength) to optimize the deflection of low mass-to-charge ratio ions. By dynamically controlling the electric field parameters, the system compensates for the magnetic field's harmful effects on specific ion types while preserving the overall ionization efficiency enhancement.
2Reliability
If the mass spectrometer is optimized for GC-MS applications with helium carrier gas, then performance for typical GC-MS analysis is improved, but sensitivity for low mass-to-charge ratio ions is reduced
Solution Approach 1:
The patent applies dynamics by making the electric field configurable and adjustable based on the analysis mode. The system can dynamically switch between optimization modes: one optimized for GC-MS applications with helium carrier gas, and another optimized for direct sample introduction with enhanced sensitivity for low mass-to-charge ratio ions. This dynamic adaptability allows the spectrometer to maintain reliable GC-MS performance when needed while achieving high sensitivity for low mass ions when required.
3Power
If thermal electrons are accelerated through the ionization chamber to ionize sample molecules, then ionization capability is achieved, but low mass ions cannot be observed due to magnetic field interference
Solution Approach 1:
The patent introduces an intermediary mechanism - the deflection electric field - that mediates between the thermal electron acceleration process and the low mass ion extraction. The electric field acts as an intermediate force that counterbalances the magnetic field's harmful interference, allowing thermal electrons to maintain their ionization capability while low mass ions are protected from trajectory bending and loss.
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 enhances ion extraction efficiency and sensitivity, allowing for high analysis sensitivity across a wide range of mass-to-charge ratios, including low values, by minimizing ion loss and optimizing the trajectory of ions during extraction.
Implementation Method 1
The thermal electrons receive a Lorentz force due to the magnetic field and travel while helically swirling around the magnetic field lines
Implementation Method 2
a deflection electric field forming unit configured to form a deflection electric field deflecting ions derived from the component generated in the ionization chamber by a direct or indirect action of the thermal electrons in a direction against a force received from the magnetic field
Implementation Method 3
The gaseous sample molecules supplied into the ionization chamber come into contact with the thermal electrons and are ionized by interaction with the thermal electrons
Data Source
AI summary
One mode of the mass spectrometer according to the present invention is a mass spectrometer including an ion source configured to ionize a component contained in a sample gas, the ion source including: an ionization chamber having an ion ejection opening and forming a space substantially partitioned from an outside inside the ionization chamber; a thermal electron supply unit configured to supply thermal electrons to an inside of the ionization chamber; a magnetic field forming unit configured to form a magnetic field inside the ionization chamber such that the thermal electrons move helically; and a deflection electric field forming unit configured to form a deflection electric field deflecting ions derived from the component generated in the ionization chamber by a direct or indirect action of the thermal electrons in a direction against a force received from the magnetic field when the ions are moving toward the ion ejection opening.