Laserspray Ionization for High Molecular Weight Mass Spectrometry
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Solution Overview
Problem
Conventional mass spectrometry techniques face limitations in analyzing high molecular weight molecules, particularly proteins, due to solubility issues and the production of predominantly singly charged ions, which restricts spatial resolution and compatibility with high-resolution mass spectrometers, and solvent-based methods can introduce artifacts like oxidation of residues.
Innovation Solution
The use of laserspray ionization (LSI) methods that produce multiply-charged ions, allowing for improved spatial resolution and compatibility with high-performance mass spectrometers, and the option for solvent-free analysis to overcome solubility restrictions and artifact issues, using a matrix composed of small molecules like dihydroxybenzoic acids and dihydroxyacetophenones, and a heated region before the mass spectrometer to enhance ion detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MALDI techniques are used for tissue imaging, then analysis of high-abundant components is achieved, but sensitivity at high spatial resolution deteriorates
Solution Approach 1:
The patent changes the ionization mechanism from conventional MALDI to LSI, operating at atmospheric pressure with a heated transfer capillary. This parameter change enables multiply-charged ion formation while maintaining high spatial resolution, resolving the contradiction between spatial resolution and sensitivity
Solution Approach 2:
The patent utilizes phase transition of the matrix material through laser ablation at atmospheric pressure, followed by thermal desorption in the heated transfer capillary. This enables efficient ion transfer while preserving spatial information, improving both sensitivity and spatial resolution
2Adaptability or versatility
If MALDI produces singly charged ions, then ionization simplicity is maintained, but compatibility with high-resolution mass spectrometers deteriorates
Solution Approach 1:
The patent changes the ionization parameters by operating at atmospheric pressure with a heated transfer capillary and optimized laser parameters. This enables formation of multiply-charged ions that are compatible with high-resolution mass spectrometers while maintaining a relatively simple laser-based ionization approach
3Reliability
If solvent-based MALDI techniques are used, then ionization efficiency is improved, but artifact formation such as oxidation deteriorates
Solution Approach 1:
The patent extracts the solvent from the ionization process, using solvent-free LSI at atmospheric pressure. This eliminates the source of oxidation artifacts while maintaining efficient ionization through direct laser ablation and thermal desorption of the matrix material
Solution Approach 2:
The patent operates in an atmospheric pressure environment with controlled gas flow through the heated transfer capillary, creating an inert-like atmosphere that prevents oxidation of analyte molecules during the ionization and transfer process
4Measurement precision
If solvent-free analysis is used, then spatial resolution is improved, but analysis of solubility-restricted compounds deteriorates
Solution Approach 1:
The patent changes the fundamental ionization parameter from solution-based to solvent-free laser ablation at atmospheric pressure. This enables direct analysis of insoluble compounds while maintaining high spatial resolution, as the laser directly ablates the sample matrix without requiring solvent dissolution
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
LSI enables the analysis of high molecular weight molecules with improved spatial resolution and fragmentation, extending the mass range of mass spectrometers and reducing artifacts, allowing for more accurate protein identification and imaging.
Implementation Method 1
Ablating the material/matrix analyte with a laser
Implementation Method 2
passing the laser-ablated material/matrix analyte through a heated region before the material/matrix analyte enters the high vacuum area of a mass spectrometer
Data Source
AI summary
Disclosed herein are systems and methods for mass spectrometry using laserspray ionization (LSI). LSI can create multiply-charged ions at atmospheric pressure for analysis and allows for analysis of high molecular weight molecules including molecules over 4000 Daltons. The analysis can be solvent-based or solvent-free. Solvent-free analysis following LSI allows for improved spatial resolution beneficial in surface and/or tissue imaging.