Mass Spectrometry Deadtime Correction via MCMC
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Solution Overview
Problem
Mass spectrometry measurements are affected by time-dependent intensity information loss due to deadtime and edge effects in time-to-digital converters (TDC), and interference from other species, leading to inaccurate mass and intensity measurements, especially in chromatographic experiments where data summation is not always optimal.
Innovation Solution
A method using a Markov Chain Monte Carlo algorithm to correct for deadtime effects and remove interferences by calculating the joint probability distribution of ion arrival rates and effective number of experiments, allowing for accurate mass and intensity measurements by analyzing the analyte in a mass spectrometer with TDC or ADC detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectra are summed to improve signal-to-noise ratio, then measurement precision improves, but deadtime effects and TDC edge effects cause mass shifts that worsen measurement accuracy
Solution Approach 1:
The invention segments the mass spectral data by retaining individual spectra rather than summing them, allowing separate analysis of each spectrum to preserve time-dependent information while still achieving improved mass measurement precision through statistical methods
Solution Approach 2:
The invention uses feedback by iteratively refining mass measurements using information from individual spectra, adjusting for deadtime effects and TDC edge effects based on observed patterns in the segmented data to improve overall measurement accuracy
2Measurement precision
If TDC threshold is set low to detect single ion arrivals, then detection sensitivity improves, but electronic noise increases causing false detections
Solution Approach 1:
The invention introduces statistical analysis as an intermediary layer between the raw TDC measurements and the final mass determination, using probability distributions to distinguish true ion signals from electronic noise while maintaining high detection sensitivity
Solution Approach 2:
The invention changes the parameter from a fixed TDC threshold to a dynamic threshold based on statistical analysis of the data distribution, allowing the effective threshold to adapt to the actual signal-to-noise conditions in each measurement
3Productivity
If detector signal is high to improve measurement speed, then productivity improves, but detector saturation causes non-linear response worsening measurement precision
Solution Approach 1:
The invention applies dynamics by using variable attenuation levels that can be adjusted based on the detected signal intensity, allowing the system to operate in the linear regime for high intensity signals while maintaining high productivity through rapid switching between attenuation states
Solution Approach 2:
The invention uses periodic action by implementing dynamic range enhancement through alternating between different attenuation levels, capturing multiple measurements at different signal levels and combining them to achieve both high speed and high precision
Data Source
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AI summary
A method of improving the fidelity of m/z dependent measurements for a species of interest in an analyte in a mass spectrometer, which method comprises the steps of acquiring raw data produced in a mass spectrometer, identifying a region within the raw data that relates to the species of interest, forming a mathematical model to calculate the joint probability distribution of the parameters effecting the m/z dependent measurements, analytically obtaining samples from the joint probability distribution to produce corrected or refined m/z dependent measurements with associated uncertainties.