GC-IMS Sample Transfer Device Bypasses Ionization Region
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Solution Overview
Problem
Conventional GC-IMS systems face challenges in detecting both positive and negative ions simultaneously due to ionization source design, leading to interference, reduced sensitivity, and difficulty in analyzing organic macromolecules, as samples are directly introduced into the ionization region, causing fragmentation and neutralization reactions.
Innovation Solution
A GC-IMS system design where the sample bypasses the ionization region, using a sample transfer device to directly transfer the sample to separate reaction regions for positive and negative ions, avoiding ionization source-induced fragmentation and neutralization, and employing electrodes to generate electric fields for ion separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the sample is directly introduced into the ionization region, then the ionization efficiency is improved, but the sample molecules are fragmented into ion fragments causing interference peaks and reduced resolution
Solution Approach 1:
The system divides the ionization process into two separate regions: an ionization region for generating reactive ions from carrier gas, and a reaction region for sample ionization. This segmentation prevents direct exposure of sample molecules to high-energy ionization, avoiding fragmentation while maintaining ionization efficiency through reactive ion transfer.
Solution Approach 2:
The invention extracts the sample introduction path from the ionization region and creates a separate reaction region. The sample bypasses the ionization region entirely and enters only the reaction region where pre-formed reactive ions are present, thereby eliminating the harmful direct ionization effect while preserving the beneficial ionization efficiency.
2Adaptability or versatility
If both positive and negative ions are measured by switching electric field, then both ion types can be detected, but they are not measured simultaneously causing loss of correlative information
Solution Approach 1:
The system separates the detection of positive and negative ions into two independent reaction regions with separate drift tubes and detection systems. This allows simultaneous measurement of both ion types without the need for electric field switching, preserving the temporal correlation between positive and negative ion signals.
Solution Approach 2:
Instead of using time-domain switching to detect different ion polarities, the invention transitions to a spatial solution with separate reaction regions and drift tubes for positive and negative ions. This dimensional change from time-based to space-based separation enables simultaneous detection while maintaining information correlation.
3Manufacturing precision
If a pulsed corona discharge ionization source is used, then soft ionization is achieved preventing sample fragmentation, but positively charged sample molecular ions react with unionized carrier gas molecules increasing analysis complexity
Solution Approach 1:
The system performs preliminary ionization of the carrier gas in a dedicated ionization region to generate reactive ions before the sample enters the reaction region. This preliminary action ensures that when sample molecules enter the reaction region, they encounter pre-formed reactive ions rather than unionized carrier gas molecules, preventing unwanted reactions while maintaining soft ionization conditions.
Solution Approach 2:
The invention introduces reactive ions as an intermediary between the carrier gas and sample molecules. Instead of direct interaction between sample molecules and unionized carrier gas, the reactive ions serve as mediators that facilitate controlled ionization reactions, simplifying the analysis by providing well-defined reaction pathways.
4Adaptability or versatility
If positive and negative ions are generated in the same ionization region, then both ion types are produced, but Coulomb attraction causes neutralization reactions reducing detection sensitivity
Solution Approach 1:
The system segments the ion generation process into separate ionization regions for positive and negative ions, or uses a single ionization region that produces reactive ions which then separately ionize samples in distinct reaction regions. This spatial separation prevents Coulomb attraction between oppositely charged ions, eliminating neutralization reactions and maintaining high detection sensitivity.
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 design enables simultaneous detection of positive and negative ions, increases detection sensitivity, and improves spectral resolution, extending the system's application to organic macromolecules by preventing ion fragmentation and neutralization, thus enhancing the analysis capability.
Implementation Method 1
Ionization effects generated by different ionization sources have a very direct influence on performance of the IMS. For example, all of the most widely used 13-sources will emit high-energy primary electrons (of 67 keV for 63Ni and of 18 keV for 3H). If the structural design in which a sample is introduced directly into the ionization region is used, when the sample passes through in the vicinity of the β-source, it will be hit by high-energy β-particles directly into molecular ion fragments
Implementation Method 2
when the sample passes through in the vicinity of the β-source, it will be hit by high-energy β-particles directly into molecular ion fragments
Implementation Method 3
Coulomb attraction forces will be generated among the positive ions and the negative ions generated in a same space of the ionization region. If no repulsion voltage is applied to the ionization region, the positive ions and the negative ions (or electrons) driven to enter the reaction region by a carrier gas flow will be neutralized due to their collision and recombination
Implementation Method 4
the positive ions and the negative ions (or electrons) driven to enter the reaction region by a carrier gas flow
Data Source
AI summary
A GC-IMS system is disclosed. The system includes a sample transfer device. The sample transfer device connects the gas chromatograph to the reaction region and, the sample from the gas chromatograph is transferred to the reaction region by the sample transfer device. With the GC-IMS system, generation of sample molecular ion fragments can be avoided so that the spectrum is easily identified; moreover, the application field of the GC-IMS system is extended to a range of analysis of organic macromolecule samples which have a high polarity, are difficult to volatilize, and are thermally instable. On the other hand, the GC-IMS system overcomes the defect of ion destruction due to neutralization reaction among positive and negative ions so as to evade the detection.