FT Quadrupole Mass Analyzer Resonant Ion Ejection for Higher m/z SNR
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Solution Overview
Problem
High intensity ion signals at lower m/z ratios obscure oscillations associated with higher m/z ions in Fourier transform mass spectrometry, degrading the signal-to-noise ratio (SNR) of the mass spectrum.
Innovation Solution
A method and system that utilize a multipole rod set in a Fourier transform mass analyzer to apply RF voltage for radial confinement and a resonant burst of AC signal to remove selected m/z ratios, converting radial oscillations into axial oscillations for improved detection, thereby enhancing the SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high intensity ion signals at lower m/z ratios are detected, then the detection sensitivity for low m/z ions is improved, but the signal-to-noise ratio for higher m/z ions deteriorates due to obscuring oscillations
Solution Approach 1:
The patent extracts and removes ions with selected m/z ratios (particularly low m/z ions) from the ion population before detection. By applying resonant AC signals to specific rod pairs, certain ions are selectively ejected from the multipole structure, preventing their oscillation signals from obscuring the detection of higher m/z ions and thereby improving the overall signal-to-noise ratio
Solution Approach 2:
The patent applies different voltages and excitation conditions to different rod pairs within the multipole structure. By selectively applying resonant AC signals to specific rod pairs corresponding to particular m/z ranges, the system creates localized selective removal zones for different ion populations, allowing optimization of detection quality for specific mass ranges
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
The method improves the signal-to-noise ratio of the mass spectrum by selectively removing low m/z ions, enhancing the quality of the resultant mass spectrum.
Implementation Method 1
applying at least one RF voltage to at least one of the rods so as to generate an RF field for radial confinement of the ions
Implementation Method 2
applying a resonant burst of an AC signal to at least one of the rods so as to remove ions having selected m/z ratios
Implementation Method 3
the fringing fields in proximity of the output end of the plurality of rods convert the radial oscillations of at least a portion of the radially excited ions into axial oscillations
Data Source
AI summary
In one aspect, a method of performing Fourier Transform (FT) mass spectrometry is disclosed, which comprises passing a plurality of ions through an FT mass analyzer comprising a plurality of rods arranged in a multipole configuration, where the plurality of rods include an input port for receiving ions and an output port through which ions can exit the mass analyzer. The method can further include applying at least one RF voltage to at least one of the rods so as to generate an RF field for radial confinement of the ions as they pass through the mass analyzer, and applying a resonant burst of an AC signal to at least one of said rods so as to remove ions having selected m/z ratios, e.g., m/z ratios within a desired range, from the ions introduced into the FT mass analyzer.