Ion Lens Voltage Control for Mass Spectrometer Sensitivity Drift
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Solution Overview
Problem
Mass spectrometers experience sensitivity drift when voltages applied to the ion optical system are adjusted to achieve a predetermined detection sensitivity, leading to inconsistent spectrum patterns and reduced identification accuracy for unknown compounds.
Innovation Solution
A mass spectrometric method that adjusts the voltage applied to a first ion lens to satisfy a specified detection sensitivity requirement while limiting the change in detection sensitivity for a second ion lens within a specified range, reducing sensitivity drift and ensuring consistent spectrum patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltages applied to ion lenses are adjusted to maximize ion detection sensitivity, then detection sensitivity is improved, but sensitivity drift occurs leading to unstable spectrum patterns
Solution Approach 1:
The patent changes the voltage parameter applied to ion lenses from maximum sensitivity optimization to a controlled range that ensures stability. Specifically, voltages are set within ranges where sensitivity changes are minimal (≤30% change for ±5V variation), transforming the operating point from peak sensitivity to stable operating region, thereby resolving the contradiction between sensitivity and stability
Solution Approach 2:
The patent预先 establishes voltage ranges with built-in stability margins before actual measurement. By determining voltage ranges where sensitivity changes remain within acceptable limits (≤30%) in advance, the system cushions against voltage fluctuations and drift, preventing spectrum pattern instability before it occurs
2Measurement precision
If voltages are adjusted to achieve predetermined spectrum patterns, then identification accuracy is improved, but sensitivity drift reduces measurement consistency
Solution Approach 1:
The patent transforms the voltage control strategy from pattern-matching optimization to stability-range control. Voltages are selected to fall within predetermined stable ranges rather than being optimized for specific spectrum patterns, ensuring that measurements remain consistent across different operating conditions while maintaining sufficient identification accuracy
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 reduces sensitivity drift and maintains consistent detection sensitivity, enhancing the accuracy of identifying unknown compounds by stabilizing the ion detection sensitivity and achieving predetermined spectrum patterns.
Implementation Method 1
The ion optical system 3 has a plurality of ion lenses 31, 32 and 33 arranged along an ion beam axis, which is a central axis of a flight path of ions
Implementation Method 2
The ions are separated from each other according to their masses by a quadrupole mass filter or similar device
Implementation Method 3
the introduced measurement-target compound is ionized by electron ionization (EI) or other appropriate methods
Data Source
AI summary
Provided is a mass spectrometric method including steps of transporting ions generated in an ion source 2 to a mass spectrometer section 4 through an ion optical system 3 having a plurality of ion lenses 31, 32 and 33, and detecting the ions after performing mass separation of the ions. The method further includes steps of: adjusting a voltage applied to a first ion lens 33 which is one of the ion lenses 31, 32 and 33 so that the detection sensitivity for an ion having a predetermined mass-to-charge ratio satisfies a previously specified requirement; and applying, to a second ion lens 32 which is one of the ion lenses 31, 32 and 33 except the first ion lens 33, a voltage at which a change in the ion detection sensitivity with respect to the voltage applied to the second ion lens 33 is within a previously specified range.