Universal Gas Analyzer Ionization Method
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Solution Overview
Problem
Conventional PTR-MS setups are limited in analyzing substances with properties similar to common air compounds, such as CO and NOx, due to primary ions reacting predominantly with dominant air components, leaving insufficient reagent ions for trace compounds.
Innovation Solution
Introducing a source gas, preferably noble gases like Kr, Xe, Ne, or Ar, into a reaction chamber, ionizing it, and then transferring the primary ions to a drift tube where the gas to be analyzed is diluted with a carrier gas of higher ionization energy to avoid protonated species formation, allowing detection of substances with similar or lower proton affinity and/or higher ionization energy than common air compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional PTR-MS uses primary ions for ionization, then substances with higher proton affinity or lower ionization energy than air compounds can be detected, but substances with similar or lower proton affinity and higher ionization energy (like CO, NOx) cannot be analyzed because primary ions react predominantly with dominant air components
Solution Approach 1:
The invention extracts and removes the dominant air components (N2, O2) from the reaction chamber by applying a strong electric field that drives these abundant molecules toward collection electrodes, leaving behind only the trace reactant compounds. This extraction of interfering substances resolves the contradiction by eliminating the competition for primary ions, thereby making reagent ions available for detecting trace compounds with similar or lower proton affinity.
Solution Approach 2:
The invention performs preliminary removal of dominant air components before the ionization and detection process. By pre-clearing the reaction chamber of N2 and O2 through electric field-driven transport, the system ensures that primary ions will not be consumed by abundant air molecules, thus preserving reagent ions for the actual analyte detection.
2Reliability
If primary ions react with dominant air components, then ionization of air compounds occurs, but insufficient reagent ions remain for trace compound detection
Solution Approach 1:
The invention extracts dominant air components from the reaction chamber using electric field-driven transport, removing the competing substrates that would otherwise consume primary ions. This extraction ensures that primary ions react with trace compounds instead, improving both the reliability of ionization for target compounds and the productivity in terms of ion yield for trace detection.
Solution Approach 2:
The invention creates a localized region with altered composition by removing dominant air components from the reaction chamber while maintaining the presence of trace compounds. This local quality change ensures that the ionization process occurs preferentially with the trace analytes rather than abundant air molecules, resolving the contradiction between reliable ionization and sufficient ion yield.
3Measurement precision
If conventional PTR-MS setup is used, then analysis of substances with higher proton affinity is possible, but analysis of substances with similar or lower proton affinity and higher ionization energy is limited
Solution Approach 1:
The invention extracts dominant air components that limit the detection range, thereby expanding the applicability to substance classes with similar or lower proton affinity and higher ionization energy. This extraction removes the fundamental limitation, allowing precise detection of previously undetectable compounds while maintaining measurement precision for existing analytes.
Solution Approach 2:
The invention transforms the PTR-MS system into a universal gas analyzer capable of detecting a broad range of substance classes including CO, NOx, and other traffic exhaust products that were previously undetectable. By removing the limitation imposed by dominant air components, the system gains multi-functionality across different analyte types while maintaining high measurement precision.
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
Enables universal gas analysis by utilizing primary ions up to the ionization energy of He, expanding the applicability of PTR-MS instruments to nearly all existing molecules, while maintaining linear ion yield with concentration for simple calibration.
Implementation Method 1
a source gas, preferably but not limited to noble gases, in particular Kr, Xe, Ne, Ar, He, is introduced to and ionized in a reaction chamber (e.g. a hollow cathode discharge)
Implementation Method 2
ionized in a reaction chamber (e.g. a hollow cathode discharge)
Implementation Method 3
the gas to be analyzed is diluted with a carrier gas of higher ionization energy to avoid protonated species formation
Implementation Method 4
The product ions that arc formed either via proton, via charge transfer or other ion molecule reactions can be analyzed by any type of mass spectrometer
Data Source
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AI summary
The invention provides a method and system for analyzing a gas for the presence of a reactant compound via reaction of primary ions of a specific type. A source gas is introduced to a reaction chamber and ionized in this chamber. The pressure in the reaction chamber is adjusted to avoid the formation of protonated species and other impurities. The primary ions generated in the reaction chamber are transferred to a drift tube. The gas to be analyzed is diluted with a carrier gas and the resulting mixture is introduced into the drift tube. The ionization energy of the carrier gas is equal to or higher than the ionization energy of the primary ions. The product ions resulting in the drift tube from a reaction of the primary ions with the reactant present in the gas to be analyzed are then detected, for example using a mass spectrometer. Preferably, an existing PTR-MS setup is used to perform the method of the present invention.