SPME Vacuum Inlet Load Lock for Mass Spectrometry
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Solution Overview
Problem
Conventional Solid Phase Micro Extraction (SPME) methods combined with Gas Chromatography (GC) and Mass Spectrometry (MS) systems face limitations in analysis time and the detection of non-volatile analytes, as GC columns restrict the types of analytes that can be analyzed and require lengthy retention times.
Innovation Solution
A pressure vessel configured as a vacuum load lock is introduced to facilitate the desorption of analytes from a SPME probe under partial vacuum conditions, using a heating element within the vessel to efficiently transfer the desorbed analytes to a mass spectrometer, allowing for faster analysis and detection of both volatile and non-volatile compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GC column separation is used for analyte analysis, then selectivity is improved, but analysis time increases to 5-10 minutes
Solution Approach 1:
The system divides the sample introduction process into two separate pressure zones: a load lock chamber for sample preparation at atmospheric pressure and a vacuum chamber for MS analysis. This segmentation allows GC-MS and direct MS analysis to operate independently in their respective pressure environments, enabling faster total analysis time while preserving the selectivity benefits of GC column separation when used.
Solution Approach 2:
The load lock chamber acts as an intermediary between the atmospheric pressure sample introduction system and the vacuum MS system. It provides a transition zone where samples can be introduced, prepared, and transferred to the vacuum chamber without compromising the vacuum environment, thereby enabling faster sample introduction while maintaining analysis quality.
2Adaptability or versatility
If GC column is used for analyte separation, then volatile analytes can be detected, but non-volatile analytes cannot be analyzed
Solution Approach 1:
The load lock chamber provides a universal sample introduction interface that accommodates both GC-MS analysis for volatile compounds and direct MS analysis for non-volatile compounds. The system can selectively operate in GC-MS mode or direct injection mode, making it versatile for analyzing different types of analytes without requiring separate systems.
3Productivity
If sample is introduced directly into vacuum chamber, then analysis speed is improved, but vacuum integrity is compromised
Solution Approach 1:
The system segments the vacuum environment from the atmospheric sample introduction zone using a load lock chamber. This allows rapid sample introduction into the load lock without affecting the vacuum chamber, maintaining vacuum integrity while enabling fast sample changes and analysis.
Solution Approach 2:
The load lock chamber serves as an intermediary buffer between atmospheric pressure and vacuum environments. Samples can be introduced rapidly into the load lock, prepared, and then transferred to the vacuum chamber, maintaining both analysis speed and vacuum integrity simultaneously.
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 approach significantly reduces analysis time, enables the detection of a broader range of analytes, and enhances analytical sensitivity by efficiently introducing samples into the mass spectrometer under controlled vacuum conditions.
Implementation Method 1
heating of the probe portion commences for causing desorption of the analytes under near (e.g., partial) vacuum conditions
Implementation Method 2
desorption component is configured for heating a probe portion (e.g., SPME fiber) of a SPME assembly for causing desorption of analytes of the sample from an extracting phase material
Data Source
AI summary
A sample introduction system configured for introducing analytes of a solid phase micro extraction (SPME) sample into an analytical instrument system (e.g., mass spectrometer) is described. The sample introduction system includes a pressure vessel configured with an inlet port via which a probe portion (e.g., SPME fiber) of a SPME assembly is received into a sealed volume of the pressure vessel. The probe portion of the SPME assembly is coated with an extracting phase material, the analytes being absorbed into and/or adsorbed onto the extracting phase material. The pressure vessel is configured for providing an environment in which desorption of the analytes from the extracting phase material occurs at a gaseous pressure which is substantially less than atmospheric pressure (e.g., less than 100 mTorr). The desorbed analytes are then directed to the vacuum chamber of the analytical instrument system via an outlet port of the pressure vessel.