Intermediate Pressure Ionization for Universal Mass Spectrometry
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Solution Overview
Problem
Current mass spectrometry technologies face challenges in efficiently ionizing both liquid and gaseous effluents from various sources, particularly for volatile and less polar compounds, and lack a single ionization source capable of handling solids, liquids, and gases with high sensitivity and accuracy.
Innovation Solution
The development of an intermediate pressure ionization region that can be heated or cooled, combined with voltage application and alternative ionization methods like discharge or photoionization, enables efficient ionization of analytes from gas chromatographs and liquid chromatographs, allowing for universal ionization in a single device, interfacing with both GC and LC systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If atmospheric pressure ionization is used for liquid chromatography, then softer ionization with less fragmentation is achieved, but identification of unknowns becomes difficult due to inability to match with standard libraries
Solution Approach 1:
The patent implements dynamic switching between two ionization modes (APCI and EI) within a single mass spectrometer system. The ionization method can be changed based on the analysis requirements, allowing the system to adapt between soft ionization for molecular weight determination and hard ionization for library matching, thereby resolving the contradiction between reduced fragmentation and identification accuracy
Solution Approach 2:
The patent creates a universal ionization system that combines both atmospheric pressure chemical ionization (APCI) and electron ionization (EI) capabilities in one instrument. This multi-functional approach allows the same mass spectrometer to perform both LC/MS with soft ionization and GC/MS with hard ionization, eliminating the need for separate instruments and resolving the identification accuracy issue
2Adaptability or versatility
If conversion from LC/MS to GC/MS is performed by breaking vacuum and interchanging ion sources, then GC/MS operation is achieved, but the process becomes time-consuming and requires vacuum breaking
Solution Approach 1:
The patent designs a universal ionization chamber that can perform both APCI and EI functions simultaneously or switch between them rapidly. The system maintains vacuum continuity while allowing ionization method changes through electronic control rather than physical source replacement, eliminating the time-consuming conversion process and vacuum breaking requirements
Solution Approach 2:
The patent introduces an intermediate pressure region that serves as a buffer between the atmospheric pressure ionization source and the vacuum mass analyzer. This intermediary chamber allows for rapid switching between ionization modes without requiring vacuum breaking, as the intermediate region can accommodate different ionization conditions while maintaining the vacuum integrity of the mass analyzer section
3Adaptability or versatility
If atmospheric pressure ionization is used for gas chromatography, then interface to GC is achieved, but volatile and less polar compounds are not efficiently ionized
Solution Approach 1:
The patent implements dynamic selection between APCI and EI ionization methods based on the analyte properties. For volatile and less polar compounds from GC, the system can switch to EI mode which provides superior ionization efficiency and characteristic fragmentation patterns, thereby maintaining high reliability across different compound types while preserving versatility in handling various effluent types
Solution Approach 2:
The patent changes the ionization parameters by switching between chemical ionization (APCI) and electron impact (EI) mechanisms. EI operates at higher energy levels with 70 eV electrons, providing efficient ionization for volatile compounds and characteristic fragmentation, while APCI operates at atmospheric pressure with lower energy. This parameter change allows optimal ionization efficiency for different compound classes
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 enhances sensitivity, facilitates computer library searchable mass spectra, and provides high-resolution, accurate mass measurement and fragmentation, enabling the analysis of a wide range of compounds with improved chromatographic resolution and reduced ion losses, overcoming limitations of existing atmospheric pressure ionization methods.
Implementation Method 1
ionized at AP using an electric discharge
Implementation Method 2
alternative ionization methods like discharge or photoionization
Implementation Method 3
Evaporation of the droplets leads to a state where the surface charge again becomes sufficiently high
Implementation Method 4
The primary ions in turn ionize the gas phase analyte molecules by either an ion-molecule process as occurs in atmospheric pressure chemical ionization (APCI), by a charge transfer process
Implementation Method 5
by a charge transfer process
Implementation Method 6
the disclosed system and method relate to an intermediate pressure ionization region for linking a first pressure region with a second pressure region of a mass analyzer
Data Source
AI summary
An ion source able to ionize liquid and gaseous effluents from interfaced liquid or gaseous separation techniques and from direct introduction of the analyte to the entrance of the ionization region. The liquid effluents from sources such as a liquid chromatograph are ionized by inlet ionization methods and the gaseous effluents from sources such as a gas chromatograph are ionized by a corona or Townsend electrical discharge, or an alpha or beta emitter, or by inlet ionization, or by photoionization. Ionization occurs in an intermediate pressure region linking atmospheric pressure and the vacuum of the mass analyzer. The source has the ability to ionize compounds from both liquid and gaseous sources, which facilitates ionization of volatile compounds separated by gas chromatography, volatile or non-volatile compounds separated by liquid chromatography, or infused into the ionization. The ionization methods can be achieved with a single configuration or with separately optimized configurations.