Ion Mobility Drift Time Calibration for Mass Spectrometry
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Solution Overview
Problem
Current ion mobility mass spectrometry techniques struggle to perform detailed studies of Electron Transfer Dissociation (ETD) fragment ion structures due to inaccuracies in ion mobility drift time measurements, which are affected by changes in instrument parameters like temperature and pressure, limiting the ability to detect precise conformational changes in peptides.
Innovation Solution
A method that involves determining an initial calibration function using multi-point external or internal calibration methods and then adjusting it during the experiment using known reference ions to generate a revised calibration function, which more accurately correlates ion mobility drift times with collision cross sections, thereby correcting for minor changes in instrument parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multi-point external or internal calibration is used to determine ion mobility drift times, then calibration function can be established, but measurement precision deteriorates due to instrument parameter changes during the experiment
Solution Approach 1:
The patent applies preliminary action by establishing a calibration function before the ion mobility experiment using multi-point external or internal calibration methods. This preliminary calibration provides a baseline relationship between drift time and collision cross section, which can then be refined during the experiment to account for parameter changes.
Solution Approach 2:
The patent implements feedback by continuously monitoring known reference ions during the ion mobility experiment and using their measured drift times to adjust and refine the calibration function. This feedback mechanism compensates for instrument parameter changes (temperature, pressure) that occur during the experiment, maintaining measurement precision throughout the experimental duration.
2Loss of information
If detailed studies of ETD fragment ion structures are performed, then conformational information can be obtained, but measurement accuracy decreases due to sensitivity to instrument parameter variations
Solution Approach 1:
The feedback principle is applied by using known reference ions as internal standards during the experiment. Their measured drift times provide real-time feedback on instrument parameter stability, allowing dynamic adjustment of the calibration function to maintain accurate conformational measurements despite parameter variations.
Solution Approach 2:
The patent addresses parameter changes by explicitly accounting for temperature and pressure variations during the experiment. The calibration function is adjusted based on these parameter changes, allowing the system to maintain measurement accuracy even as environmental conditions fluctuate during detailed ETD fragment ion structure studies.
3Ease of manufacture
If calibration function is determined before experiment, then initial correlation between drift time and collision cross section is established, but adaptability to experimental conditions deteriorates
Solution Approach 1:
The patent uses preliminary action to establish an initial calibration function before the experiment using multi-point calibration methods. This provides a starting point that is easy to establish and implement, while the subsequent feedback mechanism during the experiment adds the necessary adaptability to handle actual experimental conditions.
Solution Approach 2:
The calibration function transitions from a static pre-determined relationship to a dynamic, adaptive function that updates during the experiment. The system dynamically adjusts the calibration based on real-time measurements of known reference ions, allowing the calibration to adapt to actual experimental conditions while maintaining the simplicity of the initial establishment process.
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 enables precise measurements of collision cross sections, allowing for detailed investigations of conformational properties of peptides and molecules that were previously not possible, enhancing the accuracy of ion mobility experiments.
Implementation Method 1
an ion mobility spectrometer or separator arranged and adapted to separate ions according to their ion mobility
Implementation Method 2
a time of flight mass analyser
Data Source
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AI summary
A method of mass spectrometry is disclosed comprising passing ions through an ion mobility spectrometer 11 and acquiring first ion mobility drift time data. A calibration function is applied to the first ion mobility drift time data to determine a physico-chemical property (e.g. CCS) of the ions. Second ion mobility drift time data is then acquired and the calibration function is applied to the second ion mobility drift time data to determine the physico-chemical property of one or more known or reference ions. The calibration function is then adjusted.