REIMS Ionization Using Matrix Dilution for Lipid-Rich Tissue Analysis
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Solution Overview
Problem
Rapid evaporative ionization mass spectrometry (REIMS) techniques face low ionization yields due to strong intermolecular bonds between analyte molecules, particularly when analyzing tissues with high neutral lipid content like adipose or breast tissue, and are hindered by electrosurgical diathermy coagulation mode and sample carryover issues.
Innovation Solution
Diluting or dissolving the analyte in a matrix before collision with a surface, which reduces intermolecular bonding, facilitates ionic dissociation, and enhances ionization by fragmenting into smaller droplets, using methods like laser irradiation, ultrasonic energy, or glow discharge for dissociation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct collision of aerosol particles with collision surface is used, then ionization is enhanced, but ionization yield remains relatively low due to strong intermolecular bonds between analyte molecules
Solution Approach 1:
The patent applies preliminary action by dissolving the analyte in a matrix compound before collision with the collision surface. This pre-treatment step reduces intermolecular bonding between analyte molecules, making them more susceptible to ionization upon collision. The matrix compound facilitates ionic dissociation before the actual ionization event occurs at the collision surface.
Solution Approach 2:
The matrix compound acts as an intermediary substance between the analyte and the collision surface. It mediates the ionization process by forming a solution with the analyte that has reduced intermolecular bonds, thereby facilitating more efficient ionization when the solution collides with the collision surface. The matrix enables the analyte to be more easily ionized without direct contact with the collision surface.
2Reliability
If electrospray post-ionisation is used to enhance ion yield, then ionization is improved, but patient safety is compromised due to high voltages involved
Solution Approach 1:
The patent replaces the electrical field-based electrospray ionization method with a mechanical collision-based ionization method. Instead of using high voltage electrical fields to ionize the analyte, the patent uses physical collision of the analyte-matrix solution with a collision surface to achieve ionization. This substitution eliminates the safety hazards associated with high voltages while maintaining effective ionization.
3Measurement precision
If REIMS analysis is performed on tissues with high neutral lipid content, then tissue identification is attempted, but ionization is suppressed due to strong intermolecular bonds in lipids
Solution Approach 1:
The patent changes the physical-chemical parameters of the analyte by dissolving it in a matrix compound. This parameter change reduces the strength of intermolecular bonds between lipid molecules, making them more amenable to ionization. The matrix compound alters the molecular environment of the lipids, facilitating ionic dissociation and improving ionization efficiency for tissues with high neutral lipid content.
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 increases the ionization efficiency by ensuring more analyte molecules are ionized, improving the detection of tissues with high lipid content and reducing interference from electrosurgical procedures.
Implementation Method 1
supplying a matrix compound to the analyte such that the analyte is diluted or dissolved in, or forms first clusters with the matrix; and colliding the first clusters or first droplets of the diluted or dissolved analyte with a collision surface
Implementation Method 2
fragmenting into smaller droplets, using methods like laser irradiation
Implementation Method 3
ultrasonic energy, or glow discharge for dissociation
Implementation Method 4
laser irradiation, ultrasonic energy, or glow discharge for dissociation
Implementation Method 5
a mass spectrometric signal is obtained by subjecting a substrate to alternating electric current at radiofrequency which causes localized Joule-heating and the disruption of cells along with desorption of charged and neutral particles
Data Source
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AI summary
Method of mass spectrometry or ion mobility spectrometry comprising the steps of providing an analyte; diluting the analyte by a matrix thereby forming droplets of diluted analyte, dissolving the analyte by a matrix thereby forming droplets of dissolved analyte, or forming cluster ions with analyte and matrix; fragmenting or disintegrating these droplets or clusters; wherein the fragmenting or disintegration is by laser irradiation, ultrasonic energy, glow discharge or photoionization.