Traveling Wave Multipole Segmented Electrodes Scan Rate
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Solution Overview
Problem
Quadrupole mass analyzers face limitations in scan rate due to the transit time of ions through the device, which restricts the resolution and scan rate of mass spectrometry, as ions must remain within a stable oscillation region for RF and DC voltages during transit.
Innovation Solution
A traveling wave multipole system is introduced, where the RF and DC potentials are scanned across segments with delayed application to maintain stability for ions moving through the device, allowing for increased scan rate and resolution beyond the limitations imposed by transit time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ions are allowed to transit through the quadrupole mass analyzer, then mass analysis can be performed, but the scan rate is limited by the transit time of ions through the device
Solution Approach 1:
The quadrupole mass analyzer is divided into multiple segments along the ion transit path. Each segment can independently control RF and DC voltages, allowing different segments to operate at different voltage settings simultaneously. This enables mass range scanning across segments while ions transit through other segments, effectively decoupling the scan rate from the ion transit time and increasing overall productivity.
2Adaptability or versatility
If RF and DC voltages are scanned to cover a mass range, then multiple m/z values can be analyzed, but ions may experience unstable trajectories during voltage transitions
Solution Approach 1:
Voltage scanning is initiated in advance in segments upstream of the ion source, and continues through segments as ions transit. By the time ions reach a given segment, the voltage scanning for that segment has already been completed or is at the appropriate setting. This preliminary action ensures ions experience stable voltages throughout their transit while the system continuously scans across the full mass range, maintaining both versatility and stability.
Solution Approach 2:
The system dynamically adjusts RF and DC voltages across different segments at different times, creating a moving voltage profile that travels through the quadrupole. This dynamic voltage distribution allows continuous mass range scanning while each ion experiences a stable voltage environment during its transit, resolving the contradiction between adaptability and stability.
3Measurement precision
If the quadrupole operates as a mass filter with stable trajectories, then specific m/z ranges can be selected, but the scan rate is constrained by the time required to ramp voltages
Solution Approach 1:
The quadrupole is segmented into multiple independent voltage control zones. Each segment can maintain stable voltage settings for high-resolution mass filtering of specific m/z ranges, while other segments simultaneously scan through different mass ranges. This parallel operation across segments increases scan rate without compromising the measurement precision achieved by stable ion trajectories in each segment.
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 enables enhanced scan rates and resolutions by ensuring ions experience stable RF and DC conditions throughout their transit, overcoming the constraints of traditional quadrupole systems.
Implementation Method 1
ions are separated in a quadrupole mass filter based on the stability of their trajectories in the oscillating electric fields that are applied to the rods
Implementation Method 2
Only ions of a certain mass-to-charge ratio will be able to pass through the rods and reach the detector for a given ratio of voltages applied to the rods. Other ions have unstable trajectories and will collide with the rods
Implementation Method 3
A traveling wave multipole system is introduced, where the RF and DC potentials are scanned across segments with delayed application to maintain stability for ions moving through the device
Data Source
AI summary
A traveling wave multipole comprising two or more pairs of segmented electrodes arranged around a central axis; and a voltage supply. The voltage supply configured to supply the segments of each pair of electrodes with a different RF and DC potential; and match RF and DC potentials with a location of an ion of target m/z moving through the traveling wave multipole such that as the ion travels along the multipole the ion experiences the same RF and DC potentials while another ion of a second target m/z concurrently experiences a different RF and DC potentials at another location within the traveling wave multipole.