Mass Spectrometer Calibration via Endogenous Ion Synchronization
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Solution Overview
Problem
Mass spectrometer calibration is adversely affected by high and low frequency changes, particularly due to power supply instability and temperature variations, and existing methods using reference compounds are complex and require multiple compounds to cover the mass range, leading to interference issues and increased experimental complexity.
Innovation Solution
A method involving continuous background and experimental spectra analysis during each mass spectrometry scan to maintain synchronization with a common reference, using confidence-weighted averages to adjust individual spectra and update reference features, allowing for real-time calibration without the need for identifying ions or using multiple reference compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference compounds are used to calibrate every scan, then mass calibration precision is improved, but experimental complexity increases and signal interference occurs
Solution Approach 1:
The patent extracts the calibration function from external reference compounds and transfers it to endogenous ions naturally present in the sample. By identifying and using ions that are inherently part of the sample matrix (such as background ions or sample constituents), the method eliminates the need for separate reference compound introduction systems, thereby reducing experimental complexity while maintaining calibration precision.
Solution Approach 2:
The sample itself provides the calibration reference through endogenous ions. The method identifies ions within the sample that can serve as calibration markers, allowing the sample to self-calibrate the mass spectrum without requiring external reference materials. This self-service approach simplifies the overall experimental procedure while ensuring accurate mass measurement.
2Measurement precision
If multiple reference compounds are used to cover the complete mass range, then mass calibration accuracy is improved, but signal suppression between compounds and analytes increases
Solution Approach 1:
The patent removes external reference compounds from the system and instead utilizes endogenous ions that are naturally present in the sample or background. This extraction of the calibration function to sample-derived ions eliminates the harmful interactions and signal suppression effects that occur when multiple external reference compounds coexist with analytes in the ionization source.
3Productivity
If instrument operation continues without frequent recalibration, then productivity is improved, but calibration drift occurs due to temperature and power supply changes
Solution Approach 1:
The patent implements continuous calibration by incorporating calibration ions into every scan of the experiment. Rather than performing discrete recalibration steps, the endogenous ions provide ongoing calibration reference throughout the entire measurement process, ensuring continuous mass accuracy while maintaining high productivity. This continuous action approach eliminates calibration drift without interrupting the measurement workflow.
Data Source
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AI summary
Reference features are updated based on a previous scan during each mass spectrometry scan of a sample. Reference features with reference feature confidence values are generated from a plurality of initial scans. For each subsequent scan of a sample, sample features and sample feature confidence values are calculated. The reference features and sample features are aligned to determine common features. Constants are determined for an equation of mass of the mass spectrometer using confidence weighted regression of the common features. The constants and the equation of mass are used to calculate new mass values for the sample features. The reference features are updated using the sample features and the reference feature confidence values are recalculated in order to maintain the accuracy of reference features for calibration.