Inverse FT Ion Abundance Estimation for Decaying FTMS Signals
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Solution Overview
Problem
Existing Fourier Transform Mass Spectrometry (FTMS) methods suffer from inaccuracies and low precision in quantifying low abundance ions due to space-charge effects and ion scattering, leading to distorted peak amplitudes and reduced resolution, especially for complex molecules.
Innovation Solution
A method using inverse Fourier Transform (FT) to calculate the initial amplitude of decaying transient signals by fitting collisional and dephasing decay parameters, allowing for accurate determination of ion abundance by extrapolating to the start of the analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference compounds are used for calibration, then isotope ratio measurement accuracy is improved, but experimental complexity and analysis time increase
Solution Approach 1:
The patent extracts the calibration function from external reference compounds and embeds it within the mathematical processing of the transient signal itself. By extracting the decay characteristics (α, T) directly from each transient and using these to calculate correction factors, the system eliminates the need for separate reference compound measurements while maintaining calibration accuracy.
Solution Approach 2:
The patent creates a mathematical copy of the calibration process by modeling the transient signal decay with an exponential function and using the fitted parameters to generate correction factors. This mathematical copy replaces the physical reference compounds, providing the same calibration function through computational means rather than physical standards.
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
Improves accuracy, precision, and repeatability of ion abundance measurements by correcting for collisional and dephasing decay, applicable to both high and low abundance ions, including isotopes and isotopologues, enhancing quantitative and semi-quantitative analysis.
Implementation Method 1
Its frequency spectrum is calculated by Fourier transform (with some additional post-processing) and converted to m/z domain via calibration.
Implementation Method 2
calculating the initial amplitude of a decaying transient signal of an ion isotope using a fit of an inverse Fourier Transform (FT) of a peak of an ion within the mass spectrum
Implementation Method 3
the signal may be induced on the detection by the oscillating ions trapped by electric (orbital trapping) or a combination of electric and magnetic fields (FT ICRMS)
Data Source
AI summary
A method for determining an initial abundance of one or more of a plurality of ions in an ion sample is provided. The ion sample is analysed by a Fourier Transform Mass Spectrometer with the plurality of ions decaying over time during the analysis. The method comprises obtaining a mass spectrum of the ion sample. The mass spectrum includes a plurality of peaks indicating the abundance of each of the plurality of ions in the ion sample over an analysis time duration. The method further comprises calculating the initial amplitude of a transient signal of a first ion of the plurality of ions using a fit of an inverse Fourier Transform, FT, of a first peak of the plurality of peaks.