Quadrupole Mass Spectrometer Dynamic Settling Time
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Solution Overview
Problem
Conventional quadrupole mass spectrometers face challenges in increasing temporal resolution due to excessive waiting and scan margin times, which result in longer cycle periods and reduced data acquisition efficiency during mass scans.
Innovation Solution
A quadrupole mass spectrometer with a controller that dynamically adjusts the waiting time and scan margin based on mass differences and scan rates, allowing for shorter settling times and reduced scan margins, thereby optimizing the cycle period and improving temporal resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a settling time is provided for voltage stabilization after each mass scan, then measurement accuracy is improved, but the cycle period of mass scans increases, decreasing temporal resolution
Solution Approach 1:
The patent applies dynamics by making the settling time variable rather than fixed. The settling time is dynamically adjusted based on the mass scan range: smaller settling times are used for scans covering smaller mass ranges, while larger settling times are used for scans covering larger mass ranges. This dynamic adjustment optimizes the balance between measurement accuracy and temporal resolution, allowing the system to maintain sufficient voltage stabilization without unnecessarily extending the cycle period.
Solution Approach 2:
The patent changes the parameter of settling time based on the mass scan range. By establishing a relationship between the mass scan range and the required settling time, the system optimizes the voltage stabilization period. This parameter change allows the cycle period to be shortened when full stabilization time is not required, thereby improving temporal resolution while maintaining measurement accuracy when needed.
2Reliability
If a scan margin is provided to allow complete ion ejection, then measurement reliability is improved, but the effective analysis time is reduced, decreasing productivity
Solution Approach 1:
The patent applies dynamics by making the scan margin variable rather than fixed. The scan margin is dynamically adjusted based on the mass scan range: smaller scan margins are used for scans covering smaller mass ranges, while larger scan margins are used for scans covering larger mass ranges. This dynamic adjustment ensures reliable ion ejection and prevents signal contamination without unnecessarily reducing the effective analysis time.
Solution Approach 2:
The patent changes the scan margin parameter based on the mass scan range. By establishing an optimal scan margin for different mass scan ranges, the system ensures complete ion ejection and measurement reliability while maximizing the effective analysis time. This parameter optimization prevents excessive scan margins from reducing productivity while maintaining measurement reliability.
3Stability of the object's composition
If a fixed settling time is used for all mass scans, then voltage stabilization is ensured, but temporal resolution is reduced due to unnecessary waiting periods
Solution Approach 1:
The patent changes the settling time parameter based on the mass scan range. By establishing a relationship between the mass scan range and the required settling time, the system ensures voltage stabilization is sufficient for each specific scan while avoiding unnecessary waiting periods. This parameter optimization improves temporal resolution by reducing the cycle period when full stabilization time is not required.
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 dynamic adjustment of waiting times and scan margins shortens unnecessary waiting periods and reduces dead time, enhancing the temporal resolution of mass scans by allowing for more frequent and efficient data collection.
Implementation Method 1
The quadrupole mass filter 3 is composed of four rod electrodes (only two electrodes are shown in FIG. 6) arranged in parallel around an ion optical axis C. A voltage of ±(U+V·cos ωt) is applied to each of the rod electrodes, in which a direct-current voltage ±U and a radio-frequency voltage ±V·cos ωt are added. In accordance with this application voltage, only an ion or ions having a specific mass selectively pass through the longitudinal space, while the other ions are dispersed along the way.
Data Source
AI summary
In a scan measurement in which a mass scan is repeated across a predetermined mass range, when a voltage is returned from a termination voltage of one scan to an initiation voltage for the next scan, an undershoot or other drawbacks occur to destabilize the voltage value. Therefore, an appropriate waiting time is required. Conventionally, this waiting time has been set to be constant regardless of the analysis conditions. On the other hand, in the quadrupole mass spectrometer according to the present invention, the mass difference ΔM between the scan termination mass and the scan initiation mass is computed based on the specified mass range, and a different settling time is set in accordance with this mass difference. When the mass difference ΔM is small and hence requires only a short voltage stabilization time, a relatively short settling time is set. This shortens the cycle period of the mass scan, which increases the temporal resolution.