Quadrupole Mass Spectrometer RF Voltage Correction
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Solution Overview
Problem
The frequency-variable tuning method in quadrupole mass spectrometers requires cumbersome adjustments of mass-resolving power and m/z axis, leading to a significant workload and reduced analytical efficiency.
Innovation Solution
A quadrupole mass spectrometer with a quadrupole power source that includes a wave detector, detection output adjuster, RF power source, and DC power source, featuring correctors that maintain constant radio-frequency voltage amplitude and optimal voltage conditions when frequency changes occur, eliminating the need for manual adjustments of variable resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the frequency of the RF voltage is changed to tune the LC resonance circuit, then the tuning is achieved without adjusting inductance or capacitance components, but the mass-resolving power changes and the m/z axis becomes inaccurate
Solution Approach 1:
The patent applies parameter changes by detecting the actual frequency of the RF voltage and calculating correction values based on the frequency deviation from the standard value. The correction values are then used to adjust the DC voltage and RF voltage amplitude parameters, compensating for the effects of frequency changes and maintaining accurate mass-to-charge ratio measurements without requiring manual adjustment of inductance or capacitance components.
Solution Approach 2:
The patent implements feedback by using a frequency detection circuit to continuously monitor the RF voltage frequency and feed this information back to a correction value calculation circuit. This feedback loop enables automatic adjustment of voltage parameters based on actual frequency conditions, resolving the contradiction between ease of tuning and measurement precision by making the system self-correcting rather than requiring manual intervention.
2Measurement precision
If manual adjustment of variable resistors is performed to maintain mass-resolving power and m/z axis accuracy during frequency changes, then measurement precision is maintained, but operator workload increases significantly
Solution Approach 1:
The patent applies self-service by enabling the quadrupole power source to automatically detect frequency deviations, calculate correction values, and adjust voltage parameters without operator intervention. The system performs self-diagnosis and self-correction, eliminating the need for manual adjustment of variable resistors while maintaining measurement precision, thereby resolving the contradiction between measurement precision and analytical efficiency.
Solution Approach 2:
The patent replaces the mechanical adjustment system (manual rotation of variable resistors) with an electronic automation system consisting of frequency detection circuits, calculation circuits, and automatic voltage adjustment mechanisms. This substitution eliminates the need for physical manual operations while maintaining or improving measurement accuracy, directly addressing the contradiction between precision and productivity.
3Stability of the object's composition
If fixed inductance and capacitance values are used in the LC resonance circuit, then component stability is improved, but the frequency must be adjusted which causes voltage amplitude changes affecting mass analysis accuracy
Solution Approach 1:
The patent applies parameter changes by compensating for the effects of fixed component values through dynamic adjustment of voltage parameters. When frequency changes occur due to fixed inductance and capacitance, the system calculates correction values and adjusts the DC voltage and RF voltage amplitude to maintain accurate mass-to-charge ratio measurements, resolving the contradiction between component stability and measurement precision.
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
Automated correction processes maintain mass-resolving power and prevent m/z-axis displacement during frequency adjustments, reducing operator workload and improving analytical efficiency.
Implementation Method 1
The serial circuit of the combined capacitance C and the aforementioned inductance L functions as an LC resonance circuit. A resonance in this LC resonance circuit produces an RF voltage
Data Source
AI summary
A quadrupole power source which applies a voltage to each electrode (2a-2d) of a quadrupole mass filter (2) receives inputs of an m/z-axis correction coefficient Mcomp1 and a V-voltage correction coefficient Vcomp1 in addition to a power supply controlling voltage Qcont according to the m/z of a target ion. Vcomp1 is a reciprocal of the ratio by which a frequency is changed, while Mcomp1 is the square of the ratio by which the frequency is changed. In a detection gain adjuster section (4C), a multiplier (421) multiplies an output Vdet′ of a V-voltage adjusting amplifier (405) by Vcomp1, whereby the radio-frequency voltage produced by a radio-frequency power supply section (4A) is maintained at the same level even when the set frequency of a signal generator (411) is changed in order to tune an LC resonance circuit.