MALDI Mass Spectrometry Laser Energy Adjustment for Quantitative Analysis
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Solution Overview
Problem
MALDI mass spectrometry faces challenges in quantitative analysis due to poor reproducibility of mass spectral patterns and the need for internal standards, which are costly and complex for large molecules, and require multiple samples for analysis.
Innovation Solution
Adjusting the laser pulse energy to maintain constant early plume temperature (Tearly) ensures consistent total ion count (TIC) in MALDI spectra, allowing for the measurement of the equilibrium constant of proton exchange reactions between a matrix and an analyte, and enabling the creation of calibration curves for quantitative analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If internal standards are used for quantitative analysis in MALDI mass spectrometry, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts and eliminates the requirement for internal standards from the quantitative analysis process. By using the matrix ion signal as an internal reference and establishing a calibration curve based on analyte-to-matrix signal ratios, the method removes the need for separate internal standard substances, thereby simplifying sample preparation while maintaining quantitative accuracy
Solution Approach 2:
The matrix itself serves as the reference substance for quantitative analysis. The matrix ion signal automatically provides the normalization reference, eliminating the need for external internal standards. The system uses its own components (matrix and analyte) to perform self-calibration through the established signal ratio method
2Measurement precision
If multiple samples are prepared for calibration curve construction, then measurement precision is improved, but loss of time and productivity decrease
Solution Approach 1:
The invention merges the calibration curve construction process with the quantitative analysis process. By using the matrix ion signal as a universal reference and establishing a single calibration curve based on analyte-to-matrix signal ratios, multiple analytes can be quantified using the same calibration approach, reducing the need for separate calibration procedures for each sample
3Measurement precision
If isotope-substituted internal standards are used for large molecules, then measurement precision is improved, but cost increases significantly
Solution Approach 1:
The invention replaces expensive isotope-substituted internal standards with the readily available matrix substance as the reference. The matrix, which is already present in the sample at low cost, serves as the normalization reference, eliminating the need for expensive isotopically labeled compounds while maintaining the ability to perform accurate quantitative analysis through signal ratio measurements
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 method improves the reproducibility and efficiency of MALDI spectra, enabling quantitative analysis of analytes with reduced sample preparation complexity and cost, particularly for large molecules, by maintaining thermal equilibrium in the proton exchange reaction, facilitating accurate and straightforward quantification.
Implementation Method 1
Matrix-assisted laser desorption/ionization (MALDI) is a method allowing for ionization of chemical compounds
Implementation Method 2
measuring the equilibrium constant of a proton exchange reaction between a matrix and an analyte at constant temperature
Data Source
AI summary
A quantitative analysis method using MALDI mass spectrometry wherein laser pulse energy is adjusted is disclosed. More particularly, a method for measuring the equilibrium constant of a proton exchange reaction between a matrix and a sample at a constant temperature, by dividing an ion signal ratio by a value (concentration ratio) obtained by dividing the concentration of the sample by the concentration of the matrix, may include (i) obtaining MALDI mass spectra having constant TICs by adjusting the intensity of energy applied to a specimen having a predetermined amount of a matrix and a predetermined amount of a sample mixed therein and (ii) measuring the MALDI mass spectra obtained in step (i) for a value (ion signal ratio) obtained by dividing sample ion signal strength by matrix ion signal strength.