Sample Introduction Device for GC-IMS Trace Gas Detection
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Solution Overview
Problem
Existing sample introduction methods for GC-IMS are not suitable for rapid on-site detection without unpacking, as they often result in destructive sampling and have unsatisfactory adsorption, leading to alarm failures and false alarms.
Innovation Solution
A sample introduction device comprising a sampling unit, gas suction pump, adsorption units, piston cylinder, and desorption cylinder with a heating film and temperature sensor, allowing for direct suction of gas samples, adsorption, and subsequent thermal desorption for analysis without unpacking, using adsorbents to pre-concentrate volatile and semi-volatile molecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If headspace sampling methods are used, then complex pretreatment can be omitted and rapid detection is achieved, but samples are destructively obtained and not suitable for trace gas detection without unpacking
Solution Approach 1:
The patent employs a porous adsorption ribbon as the core sampling medium. The porous structure provides large surface area for adsorption, enabling efficient capture of trace gas molecules directly from the environment without unpacking, while maintaining rapid detection capability through the ribbon's thin profile and high permeability.
Solution Approach 2:
The adsorption ribbon serves as an intermediary between the trace gas sample and the GC-IMS detector. It temporarily holds the adsorbed samples and transports them to the desorption device, enabling non-destructive sampling and direct introduction of trace gases without complex pretreatment.
2Quantity of substance
If adsorption methods are used for sample collection, then samples can be concentrated, but adsorption effect is unsatisfactory leading to alarm failures and false alarms
Solution Approach 1:
The patent uses composite adsorbent materials in the adsorption ribbon, combining multiple adsorption mechanisms (physisorption and chemisorption) to enhance overall adsorption capacity and selectivity. This composite approach improves both sample concentration efficiency and detection reliability by reducing false alarms through better target analyte discrimination.
Solution Approach 2:
The adsorption ribbon is designed with non-uniform adsorbent distribution, placing different adsorbent materials in specific zones along the ribbon length. This local quality variation optimizes adsorption for different sample types and concentrations, improving both concentration efficiency and detection accuracy for specific target compounds.
3Speed
If thermal desorption is used for sample introduction, then samples can be rapidly introduced to GC-IMS, but device complexity increases
Solution Approach 1:
The patent integrates the thermal desorption chamber with the GC inlet system, combining two functions (desorption and sample introduction) into a single integrated interface. This merging reduces device complexity while maintaining rapid sample introduction capability, as the heated ribbon directly introduces desorbed samples to the GC column without additional transfer mechanisms.
Solution Approach 2:
The patent extracts the adsorption function from the main GC-IMS system by using a separate, removable adsorption ribbon that can be independently heated and replaced. This extraction simplifies the overall device structure, allowing rapid sample introduction through a simple heating process while keeping the main instrument complexity low.
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 rapid, non-destructive sampling and analysis of multiple samples, reducing preparation time, improving handling capacity, and lowering the detection limit of testing devices while minimizing false alerts.
Implementation Method 1
using adsorbents to pre-concentrate volatile and semi-volatile molecules
Implementation Method 2
thermal desorption for analysis without unpacking
Data Source
AI summary
A sample introduction device comprises a sampling unit, a gas suction pump, adsorption units, a piston cylinder and a desorption cylinder that comprises a desorption chamber, a carrier-gas inlet, a split/purge vent and an analyzer nozzle communicating with the desorption chamber. A heating film and a temperature sensor are provided on outer wall of the desorption cylinder. The piston cylinder above the desorption cylinder comprises two piston chambers, each of which is provided with the adsorption unit and in communication with the desorption chamber. The piston cylinder comprises a sample-gas inlet connected to the sampling unit and a gas-suction-pump orifice connected to the gas suction pump, each of which can communicate with both piston chambers. Each adsorption unit comprises an adsorption cylinder-like screen for holding adsorbents and a piston rod slidably mounted in the piston chamber. Each adsorption cylinder-like screen can simultaneously communicate with the sample-gas inlet and gas-suction-pump orifice.