Pulsed Sampling Ion Mobility Spectrometer for Sensitivity
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Solution Overview
Problem
Conventional ion mobility spectrometers face reduced detection sensitivity due to semi-permeable membranes blocking samples while attempting to exclude environmental background interference, leading to compromised performance in harsh external environments.
Innovation Solution
A pulsed sampling-based ion mobility spectrometer design featuring a sampling device with a sampling head and pipe, a valve assembly for controlled gas flow, and integrated dual-mode full-ceramic migration tubes, enabling efficient pulsed sampling and minimizing external environment impact through precise gas circulation and purification paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a semi-permeable membrane is used to block environmental background interference, then environmental adaptability is improved, but detection sensitivity deteriorates because most samples are blocked along with the background interference
Solution Approach 1:
The patent extracts and removes the semi-permeable membrane from the system entirely, replacing it with a pulsed sampling mechanism that directly introduces samples without membrane filtration. This eliminates the blocking effect that prevented samples from passing through while allowing environmental background to be managed through alternative means (pulsed sampling timing and gas flow control).
Solution Approach 2:
The patent implements periodic pulsed sampling where the sampling valve opens briefly at specific intervals to allow sample introduction, then closes to prevent environmental background interference. This periodic action enables selective sample intake without continuous exposure to environmental contaminants, resolving the contradiction between blocking background interference and allowing sample passage.
2Adaptability or versatility
If a membrane type sample introduction method is used to isolate external environment background, then environmental adaptability is improved, but detection sensitivity deteriorates due to sample blocking
Solution Approach 1:
The patent removes the membrane component entirely from the sample introduction system, replacing it with a valve-controlled direct sampling approach. This extraction eliminates the fundamental blocking problem that prevented sufficient sample quantity from reaching the detection chamber while maintaining environmental isolation through controlled pulsed sampling.
Solution Approach 2:
The patent uses controlled gas flow and pressure differential through the sampling valve to introduce samples pneumatically without mechanical membrane barriers. The gas flow dynamics enable sample transport into the detection chamber while the valve timing prevents environmental background contamination, achieving both adequate sample quantity and environmental adaptability.
3Measurement precision
If pulsed sampling is implemented with minimal sample intake, then detection sensitivity is enhanced, but device complexity increases due to additional valve assembly and gas path control
Solution Approach 1:
The sampling valve assembly serves multiple functions: it controls sample introduction timing, regulates gas flow direction, prevents environmental background ingress, and enables pulsed sampling operation. By making this single component multi-functional, the patent achieves enhanced detection sensitivity through minimal sample intake without proportionally increasing overall device complexity.
Solution Approach 2:
The patent combines the sampling valve, gas flow control, and environmental isolation functions into an integrated gas path system. The sampling valve is positioned to simultaneously control sample introduction and prevent background contamination, merging multiple control functions into a unified system that enhances sensitivity without adding separate complex subsystems.
Data Source
AI summary
There are provided an ion mobility spectrometer and a sniffer. The ion mobility spectrometer includes: an ion migration tube; a sampling gas path having a sampling device configured to temporarily store a sample gas collected by a sampling head in a sampling pipe; a sample introduction gas path having two ends in communication with the gas inlet and outlet of the ion migration tube respectively, and configured to introduce a carrier gas within the ion migration tube into the sampling pipe and to carry a sample gas temporarily stored in the sampling pipe into the ion migration tube; and a valve assembly configured to only allow gas to flow from the sampling device to the sampling pipe in a sampling state, and to only allow gas to flow from the ion migration tube through the sampling pipe back to the ion migration tube in a sample introduction state.