IRMS Sample Introduction with Differential Solvent Ion Separation
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Solution Overview
Problem
Current methods fail to effectively reduce the organic solvent/organic sample ratio to ultra-low levels required for accurate isotopic analysis in isotope ratio mass spectrometry, leading to high background interference from solvent molecules.
Innovation Solution
A sample introduction system that ionizes the sample before decomposition, using a spray ionization source and a separation chamber to separate sample ions from solvent ions and vapors, allowing only sample ions to proceed for further analysis, while solvent components are diverted or lost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If liquid chromatography is coupled to IRMS using conventional methods, then sample separation is achieved, but solvent interference remains high preventing accurate isotopic analysis
Solution Approach 1:
The system segments the solvent removal process into multiple stages: initial desolvation in the spray ionization source, followed by differential mobility separation that further separates remaining solvent ions from sample ions. This multi-stage approach achieves the ultra-low solvent/sample ratio better than 1:100 required for accurate isotopic analysis.
Solution Approach 2:
The patent introduces an intermediary differential mobility separation chamber between the liquid chromatography system and the IRMS. This intermediary device uses electric fields to separate ions based on mobility, effectively removing solvent ions while transmitting sample ions to the mass spectrometer, thereby eliminating solvent interference.
2Manufacturing precision
If organic mobile phase is used for sample separation, then separation efficiency is improved, but solvent background in mass spectrum increases
Solution Approach 1:
The system extracts solvent ions from the ion stream using differential mobility separation. The separation chamber applies electric fields that cause solvent ions and sample ions to follow different trajectories based on their mobility differences, effectively taking out the harmful solvent ions while retaining the sample ions for analysis.
Solution Approach 2:
The patent changes the physical parameters of the ion stream by applying varying electric field strengths and configurations in the differential mobility separation chamber. By adjusting these parameters, the system optimizes the separation between solvent and sample ions, allowing efficient solvent removal while maintaining separation efficiency with organic mobile phases.
3Object-affected harmful factors
If solvent/sample ratio is reduced to ultra-low levels, then background noise is reduced, but system complexity increases
Solution Approach 1:
The spray ionization source performs multiple functions: it ionizes the sample, initiates desolvation, and provides initial separation of solvent and sample ions. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in system complexity while achieving ultra-low solvent/sample ratios.
Solution Approach 2:
The differential mobility separation operates continuously throughout the ion transmission path, constantly removing solvent ions as they are formed or introduced. This continuous action maintains ultra-low solvent levels without requiring complex intermittent processing steps or additional processing stages.
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 solvent interference, enabling precise isotopic ratio measurement by achieving the necessary ultra-low solvent/sample ratio, thereby improving quantitation and reducing background noise in the isotopic spectrum.
Implementation Method 1
ionizes the sample before decomposition, using a spray ionization source
Implementation Method 2
a separation chamber to separate sample ions from solvent ions and vapors
Implementation Method 3
The desolvation chamber includes a heated channel which heats and desolvates the ionized sample
Data Source
AI summary
A sample introduction system for a spectrometer comprises a desolvation region that receives or generates sample ions from a solvent matrix and removes at least some of the solvent matrix from the sample ions. A separation chamber downstream of the desolvation region has a separation chamber inlet communicating with the desolvation region, for receiving the desolvated sample ions along with non-ionised solvent and solvent ion vapours. The separation chamber has electrodes for generating an electric field within the separation chamber, defining a first flow path for sample ions between the separation chamber inlet and a separation chamber outlet. Unwanted solvent ions and non-ionised solvent vapours are directed away from the separation chamber outlet. The sample introduction system has a reaction chamber with an inlet communicating with the separation chamber outlet, for receiving the sample ions from the separation chamber and for decomposing the received ions into smaller products.