Quadrupole Mass Filter Voltage Control for Single-Band Ion Transmission
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Solution Overview
Problem
Conventional quadrupole mass filters face challenges in achieving high mass resolution and fast mass separation while preventing the simultaneous transmission of ions across multiple mass-to-charge ratio ranges, as the 'scan line' may overlap with multiple stability regions, leading to undesired ion transmission.
Innovation Solution
Applying a main quadrupolar voltage, an auxiliary quadrupolar voltage, and a dipolar voltage to the quadrupole device, with the dipolar voltage being phased 180° out of phase across opposing electrodes, to selectively attenuate ions corresponding to unwanted stability regions, ensuring only ions within a single mass-to-charge ratio range are transmitted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single auxiliary quadrupolar voltage is applied to create X-band stability regions, then high mass resolution and fast mass separation are achieved, but ions from multiple mass-to-charge ratio ranges are simultaneously transmitted due to scan line overlap with multiple stability regions
Solution Approach 1:
The patent extracts and removes the harmful effect of simultaneous multi-region transmission by applying a dipolar voltage that selectively destabilizes ions in unwanted stability regions while preserving the beneficial high-resolution transmission in the desired X-band region
Solution Approach 2:
The patent changes the operational parameters by introducing a dipolar voltage component that modifies the stability diagram, creating selective instability in specific mass-to-charge ratio ranges while maintaining stability in the target region
2Device complexity
If conventional quadrupole operation is used with main RF and DC voltages, then device simplicity is maintained, but mass resolution and mass separation speed are insufficient
Solution Approach 1:
The patent applies periodic auxiliary quadrupolar and dipolar voltages at specific frequencies to the quadrupole electrodes, creating time-dependent stability regions that enable high mass resolution through repeated cycles of ion confinement and ejection
Solution Approach 2:
The patent introduces dynamic voltage modulation with auxiliary quadrupolar and dipolar components that create time-varying stability diagrams, allowing the quadrupole to transition between different operational states for enhanced mass separation
3Device complexity
If conventional quadrupole operation is used with main RF and DC voltages, then device simplicity is maintained, but fast mass separation is not achieved
Solution Approach 1:
The periodic application of auxiliary quadrupolar voltages creates rapid oscillations in the stability regions, enabling fast mass separation through repeated cycles of ion confinement and ejection at high frequencies
Solution Approach 2:
The dynamic modulation of voltages creates time-varying stability boundaries that rapidly shift and reshape, accelerating the separation process by creating multiple opportunities per cycle for ion ejection from unwanted regions
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 allows for high mass resolution and fast mass separation while preventing the transmission of undesired ions, maintaining device simplicity and cost-effectiveness by avoiding the need for additional hardware or complex control systems.
Implementation Method 1
applying a dipolar voltage to the quadrupole device... applying a first phase of the repeating (AC or RF) dipolar voltage waveform to one of the electrodes of the quadrupole device, and the opposite phase of the repeating (AC or RF) dipolar voltage waveform (180° out of phase) to the opposite electrode
Data Source
AI summary
A method of operating a quadrupole device (10) is disclosed. A voltage source (12) applies a main quadrupolar voltage, an auxiliary quadrupolar voltage and a dipolar voltage to the quadrupole device (10). This may be done such that only ions corresponding to a single X-band, X-band-like, Y-band or Y-band-like stability region are transmitted by the quadrupole device (10).