TOF Mass Spectrometer Drift Correction via Background Ion Calibration
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Solution Overview
Problem
Time-of-flight drift in mass spectrometers leads to less precise mass measurements due to environmental changes, and existing calibration methods using lock masses are prone to errors and statistical variations, especially in rich spectra.
Innovation Solution
The method involves identifying and grouping mass spectral peaks with similar time-of-flight values across spectra, applying a correction factor to correct for time-of-flight drift, and utilizing naturally occurring background ions for calibration, which eliminates the need for continuous infusion of calibrants and reduces statistical variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dilute background calibrant is used, then ionization capacity is maintained, but drift estimation precision deteriorates due to low concentration
Solution Approach 1:
The system utilizes background ions that are naturally present in the sample matrix to perform drift correction. These ions are already part of the sample composition and provide sufficient signal intensity for accurate drift estimation without requiring additional calibrant infusion.
Solution Approach 2:
The method changes the approach from using dilute external calibrants to utilizing concentrated background ions inherent to the sample. This parameter change in ion source allows simultaneous maintenance of ionization capacity and achievement of precise drift estimation.
2Measurement precision
If lock mass identification is performed in rich spectra, then calibration can be applied, but error risk increases due to difficulty in identifying the correct lock mass peak
Solution Approach 1:
The system performs automatic identification of background ions based on their inherent characteristics and persistence across spectra. The algorithm autonomously detects and selects appropriate reference ions without requiring user intervention or manual peak assignment.
Solution Approach 2:
The system uses feedback from multiple spectra to identify persistent background ions. By analyzing the consistency and persistence of ions across multiple measurements, the algorithm provides feedback to confirm correct identification of background ions, reducing error risk in complex spectra.
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 improves mass precision by accurately correcting for time-of-flight drift without requiring continuous calibrant infusion, leveraging naturally occurring ions to provide a more stable and precise mass calibration across multiple samples.
Implementation Method 1
A time-of-flight mass spectrometer (TOF-MS) can be used to determine a mass of an ion by accelerating the ion along a flight path (e.g., using an electric field), measuring a flight time of the ion
Implementation Method 2
accelerating the ion along a flight path (e.g., using an electric field)
Data Source
AI summary
A method of correcting time-of-flight drift in a mass spectrometer by identifying mass spectral peaks of ions in spectra, detecting ions having substantially the same mass across spectra, determining a time-of-flight drift of the detected ions, and correcting the time-of-flight drift of the detected ions by applying a correction factor to each respective time-of-flight.