Ligand Compound Ion Stabilization in Mass Spectrometry
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Solution Overview
Problem
Mass spectrometry faces challenges in precisely and reliably quantifying analytes due to variations in ligand forming substances, which affect the ratio of reactant ions to ligand ions, leading to inconsistent ionization efficiencies and difficulties in identifying and quantifying analytes, especially with changing partial pressures of substances like water in the reaction volume.
Innovation Solution
The introduction of ligand compound ions formed from reactant ions and a dopant substance into the reaction volume, providing a higher binding energy than the reactant ions and ligand forming substance, stabilizes ionization and maintains consistent ionization efficiencies by replacing ligand forming substances bound to reactant ions, thus ensuring reproducible and precise quantification of analytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the partial pressure of ligand forming substance in the reaction volume is increased to maximize collision frequency, then the ionization efficiency for some analytes is improved, but the ionization efficiency for other analytes decreases due to formation of ligand ions
Solution Approach 1:
A dopant substance is introduced as an intermediary that preferentially binds to reactant ions to form stable ligand compound ions. These dopant-ligand compound ions serve as controlled intermediaries that reduce the uncontrolled formation of ligand ions from ligand forming substances, thereby stabilizing the ionization process and improving quantification reliability while maintaining adequate collision frequency
Solution Approach 2:
The invention changes the chemical composition parameter of the reaction volume by introducing a dopant substance with specific binding characteristics. This parameter change alters the equilibrium between reactant ions, ligand ions, and ligand compound ions, enabling consistent ionization efficiency across different analytes despite variations in ligand forming substance partial pressure
2Quantity of substance
If electron ionisation or other hard ionisation methods are used to produce reactant ions, then sufficient reactant ions are available for chemical ionisation, but excessive fragmentation of analytes occurs reducing molecular identity preservation
Solution Approach 1:
The dopant substance acts as a mediator that softens the ionization process. By forming stable ligand compound ions with reactant ions, the dopant reduces the energy transfer during analyte collisions, preventing excessive fragmentation while maintaining sufficient reaction rates for effective ionization
Solution Approach 2:
The invention changes the energy transfer parameter in the ionization process by introducing dopant-containing ligand compound ions. These modified ions transfer energy more gently to analytes during collisions, preserving molecular structure while maintaining ionization efficiency
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 ensures stable and reproducible ionization of analytes, maintaining consistent ionization efficiencies even with changes in the partial pressure of ligand forming substances, thereby enhancing the precision and reliability of mass spectrometry results.
Implementation Method 1
ligand compound ions formed from reactant ions and a dopant substance
Implementation Method 2
the sample with the analytes is introduced into the reaction volume to react with the ligand compound ions to form adduct ions and a neutral byproduct
Implementation Method 3
Mass spectrometry usually involves the measurement of the mass-to-charge ratio of ionised analytes or analyte ions, respectively. Thus, in a first step, the analytes in the sample, which are typically neutral atoms or molecules, need to be ionised and transferred to a mass analyser. Thereby, chemical ionisation is particularly advantageous because this technique results in minimal fragmentation of the analytes as well as a high degree of preservation of molecular identity and structure of the analytes.
Data Source
Figure 1~3
Figure 4
Figure 5a~5b
AI summary
The invention relates to a chemical ionisation method, in particular an adduct ionisation method, for ionising a sample including analytes to be ionised, wherein ligand compound ions formed from reactant ions and a dopant substance are made available in a reaction volume (2), wherein said sample with said analytes is introduced into said reaction volume (2) to react with said ligand compound ions to form adduct ions and a neutral byproduct, said adduct ions including ionised analytes being adducts of said reactant ions and the respective said analytes, wherein said reactant ions and said dopant substance provide a higher binding energy when binding together to said ligand compound ions than a binding energy said reactant ions and a ligand forming substance provide when binding together, wherein said ligand forming substance is present at least in traces in said reaction volume (2) when said sample with said analytes react with said ligand compound ions to form said adduct ions and said neutral byproduct. Furthermore, the invention relates to An ion molecule reactor (1) for ionising a sample including analytes to be ionised with the chemical ionisation method according to one of claims 1 to 11, in particular for use with a mass spectrometer (100), including: a reaction volume (2) adapted for ionising inside said reaction volume (2)said sample including said analytes to be ionised by chemical ionisation, in particular adduct ionisation, wherein inside of said reaction volume (2) ligand compound ions formed from reactant ions and a dopant substance can be made available to react with said sample including said analytes to form adduct ions and a neutral byproduct, said adduct ions including ionised analytes being adducts of said reactant ions and the respective said analytes, at least one sample inlet (4) for introducing said sample including said analytes into said reaction volume (2); at least one reactant inlet (5, 6) for introducing at least one substance into said reaction volume (2) for making said ligand compound ions available inside said reaction volume (2); and an outlet (7) for letting out said adduct ions from said reaction volume (2).