Two-Step Desorption Ionization for Mass Spectrometry
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Solution Overview
Problem
Existing mass spectrometry methods face challenges with reduced ionization efficiency due to energy carrier degradation and limited desorption modes, leading to decreased sensitivity and inability to achieve soft ionization of weakly polar and polar analytes, especially when analyte ions collide with vacuum interface walls and fail to maintain optimal gas pressures.
Innovation Solution
A sample desorption and ionization device with a two-step process, utilizing a first gas pressure region for desorption and a second gas pressure region for soft ionization, where the analyte is heated and then interacts with activated gas molecules, optimizing gas pressures between 50-350 Pa to enhance ionization efficiency and broaden analyte applicability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one-step ionization method is used, then the structure is simple, but the ionization efficiency is reduced due to energy carrier degradation
Solution Approach 1:
The patent divides the ionization process into two distinct steps: desorption and ionization. The desorption step uses thermal energy to release analyte molecules from the sample surface, while the ionization step uses activated gas molecules to ionize the desorbed analyte. This segmentation prevents energy carrier degradation by using different energy carriers for each step, thereby maintaining high ionization efficiency while avoiding the limitations of one-step methods.
2Productivity
If atmospheric pressure ionization is used, then desorption and ionization can occur simultaneously, but analyte ions suffer loss due to colliding with vacuum interface walls
Solution Approach 1:
The patent introduces an intermediary region between the atmospheric pressure desorption zone and the vacuum ionization zone. This intermediary region allows desorbed analyte molecules to be transferred from the atmospheric pressure environment to the vacuum environment without direct contact with vacuum interface walls. The gas flow in this intermediary region acts as a mediator, carrying the analyte molecules smoothly across the pressure boundary and reducing ion loss from wall collisions.
3Device complexity
If atmospheric pressure ionization is used, then the process is simplified, but optimal gas pressure for soft ionization cannot be obtained
Solution Approach 1:
The patent applies local quality by creating different gas pressure conditions in different regions of the instrument. The desorption region operates at atmospheric pressure to facilitate efficient analyte release, while the ionization region operates at optimized low pressure (50-350 Pa) to enable soft ionization of weakly polar and polar substances. This spatial variation in gas pressure quality allows each region to operate under its optimal conditions, achieving both simplified process and high measurement precision.
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 improves ionization efficiency and expands the range of analytes that can be analyzed, reducing ion loss and enabling effective soft ionization of previously difficult-to-analyze compounds like alkanes and halogenated alkanes.
Implementation Method 1
a heating desorption device, disposed in the first gas pressure region and carrying a sample and heating the sample, an analyte in the sample is desorbed from the sample under a heating action
Implementation Method 2
a soft ionization source converting gas molecules in the second gas pressure region into activated gas molecules, so that the analyte, entering the second gas pressure region, realizes soft ionization after interacting with the activated gas molecules
Data Source
AI summary
The present disclosure provides a sample desorption ionization device and analysis method for a mass spectrometer. The device has a first gas pressure region and a second gas pressure region lower than the first gas pressure region. The device includes: a heating desorption device, carrying a sample and heating the sample, an analyte in the sample is desorbed from the sample under a heating action and then enters the first gas pressure region; a vacuum interface component, connected with the first gas pressure region and the second gas pressure region, and causing the analyte to enter the second gas pressure region from the first gas pressure region under the drive of a gas flow; and a soft ionization source, converting gas molecules in the second gas pressure region into activated gas molecules, the analyte entering the second gas pressure region realizes soft ionization after interacting with the activated gas molecules.