Vacuum-Assisted Sorbent Extraction for Cleaner GCMS Sample Prep
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Solution Overview
Problem
Existing GCMS sample preparation techniques struggle to effectively recover GC-compatible compounds, exclude non-GC-compatible compounds, reduce volatile sample matrix interference, and maintain analyzer cleanliness, while being sensitive to moisture and requiring manual handling.
Innovation Solution
The Matrix-Accelerated Vacuum-Assisted Sorbent Extraction (MA-VASE) method uses a system with independently controlled temperature zones and a vacuum sleeve to diffusively transfer volatile compounds to sorbents, eliminating non-volatile compounds and moisture in a closed system, allowing automated sample preparation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct contact extraction techniques (solvent extraction, SPME, SBSE) are used to extract GCMS-compatible compounds, then extraction efficiency is improved, but non-volatile compounds and moisture are co-extracted causing matrix interference and analyzer contamination
Solution Approach 1:
The system divides the extraction process into distinct stages: headspace equilibration, vacuum-assisted transfer, and sorbent trapping. This segmentation allows volatile compounds to be selectively extracted while leaving non-volatile matrix components behind in the original sample container.
Solution Approach 2:
The invention extracts only the volatile fraction of the sample by utilizing the headspace above the liquid sample. By applying vacuum and heating, volatile compounds are transferred to the sorbent while non-volatile compounds remain in the original matrix, effectively separating desired analytes from interfering substances.
2Quantity of substance
If excess water is injected into GCMS, then sample volume is increased, but ionization efficiency decreases and column damage occurs
Solution Approach 1:
The system changes the physical state and concentration parameters of water in the sample by using vacuum and heat to evaporate water from the liquid matrix before injection. This reduces water content from liquid phase to vapor phase, then removes it entirely, preventing ionization suppression while maintaining analyte concentration.
Solution Approach 2:
The invention utilizes phase transition of water from liquid to vapor through heating under vacuum conditions. This phase change allows water to be separated from the analytes and removed from the system, preventing the harmful effects of excess water on GCMS performance.
3Ease of operation
If manual sample preparation is used, then procedure flexibility is maintained, but analysis time increases and carryover occurs
Solution Approach 1:
The system enables automated sample preparation where the apparatus performs vacuum application, heating, and compound transfer without manual intervention. The self-contained design with integrated vacuum pump, heating elements, and sorbent traps allows multiple samples to be processed automatically, reducing both time and carryover risks.
4Shape
If thermal energy is increased to extract higher boiling point compounds, then boiling point range is extended, but volatile matrix components are also co-extracted
Solution Approach 1:
The invention adds the vacuum dimension to the thermal extraction process. By combining reduced pressure with controlled heating, the system achieves lower extraction temperatures than conventional thermal extraction, selectively volatilizing target compounds while leaving higher boiling point matrix components behind.
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
MA-VASE improves extraction efficiency, extends the boiling point range of compatible compounds, reduces matrix interference, and maintains analyzer cleanliness, enabling automated analysis of hundreds of samples with minimal carryover and artifact formation.
Implementation Method 1
A vacuum can be drawn in the system
Implementation Method 2
A vacuum can be drawn in the system
Implementation Method 3
the temperatures of three zones—zone A at the bottom of the sample vial, zone B in the headspace of the sample vial, and zone C at the sorbent of the sorbent extraction device—can be independently controlled
Implementation Method 4
the temperatures of three zones—zone A at the bottom of the sample vial, zone B in the headspace of the sample vial, and zone C at the sorbent of the sorbent extraction device—can be independently controlled
Implementation Method 5
one or more volatile and/or semi-volatile compounds of the sample can be transferred to the sorbent
Data Source
AI summary
Techniques disclosed herein can improve the extraction of chemicals prior to analysis by GC or GCMS. A liquid or solid sample can be placed in a sample container of a closed system under vacuum that further includes a sample extraction device. The assembly can be placed in a 3-zone heater that can separately control the temperature of the bottom of the sample container, the top of the sample container, and the sample extraction device. Vapor flux from the bottom of the sample container into the headspace of the sample container can deliver compounds of interest to the sample extraction device, whereas matrix compounds can re-condense in the headspace of the sample container to avoid delivery to the sample extraction device. Extraction can continue until substantial transfer of compounds of interest to the sorbent occurs, followed by thermal desorption of the extract into a GCMS for analysis.