Quadrupole Ion Trap Phase-Controlled Waveform Synthesizer
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Solution Overview
Problem
Conventional quadrupole ion trap (QIT) mass spectrometers face challenges with scattered mass spectral outcomes and substantial deviations due to ion-ion interactions when dealing with large numbers of molecular sample ions, limiting the accuracy and range of mass spectrometry.
Innovation Solution
A QIT apparatus with a phase-controlled waveform synthesizer generates a main RF waveform with sinuous and phase conjunction segments to order micro motions of trapped ions, allowing for constant-phase conjunction modulation, which stabilizes ion motion and extends the mass scan range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of molecular sample ions is increased to handle large-scale samples, then the quantity of substance analyzed increases, but ion-ion interactions become non-negligible and induce randomness causing scattered spectral outcomes and substantial deviations
Solution Approach 1:
The patent applies constant-phase conjunction modulation to the main RF waveform, transforming it from a conventional sine wave to a modulated waveform with specific phase characteristics. This parameter change in the RF field stabilizes ion motion dynamics even with large numbers of ions, preventing the scattering and deviations caused by ion-ion interactions while maintaining high ion population for abundant sampling.
2Ease of operation
If conventional constant-frequency RF trapping is used, then the system operation is simple, but the mass scan range is limited within a relatively small range due to physical limitations of amplitude ramping
Solution Approach 1:
The patent implements dynamic modulation of the main RF waveform amplitude using constant-phase conjunction, allowing the RF amplitude to vary systematically during mass scanning. This dynamic approach replaces the limited static amplitude ramping method, enabling a much wider mass scan range while maintaining stable ion trapping and simple operational control through automated waveform generation.
3Reliability
If buffer gas cooling is applied to slow down ion motion for better control, then the motion control improves, but ion-ion interactions intervene in the kinetics of buffer gas cooling and induce additional randomness
Solution Approach 1:
The patent applies constant-phase conjunction modulation to the main RF waveform before ion-ion interactions can significantly disrupt the buffer gas cooling kinetics. This preliminary action stabilizes the ion motion dynamics and prevents the development of randomness in the spectrometric path, allowing buffer gas cooling to function effectively even with large numbers of ions present.
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 enhances mass spectrometry resolution and linearity, reducing ion-ion interaction-induced randomness and enabling more accurate and wider-range mass scans by synchronizing ion motion and maintaining effective buffer-gas cooling.
Implementation Method 1
The phase-controlled waveform synthesizer is configured to generate a main radio frequency (RF) waveform for the main electrode. The main RF waveform includes a plurality of sinuous waveform segments each of which is a part of a sine wave, and a plurality of phase conjunction segments each of which is non-sinuous.
Implementation Method 2
In practice, since buffer gas cooling may be used to slow down the motion of ionized particles for better motion control, a damping correction due to buffer-gas cooling can be added to the Mathieu equation
Implementation Method 3
a quadrupole ion trap (QIT) composed of a hyperbolic ring electrode and two hyperbolic end-cap electrodes to confine ionized particles therein. The ring electrode is fed with a main radio frequency (RF) waveform, and the two end-cap electrodes are fed with an auxiliary waveform, thereby trapping the ionized particles.
Data Source
AI summary
A quadrupole ion trap apparatus includes a main electrode, a first end-cap electrode, a second end-cap electrode, and a phase-controlled waveform synthesizer. The phase-controlled waveform synthesizer generates a main RE waveform for the main electrode. The main RE waveform includes a plurality of sinuous waveform segments each of which is a part of a sine wave, and a plurality of phase conjunction segments each of which is non-sinuous. Each of the sinuous waveform segments is bridged to another sinuous waveform segment via one of the phase conjunction segments, so as to perform ordering of micro motions of sample ions trapped by the electrodes.