Mass Spectrometer Voltage Controller for Mode Switching
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Solution Overview
Problem
Conventional tandem mass spectrometers face issues with unintended electric discharge between closely located electrodes during switching operations between positive and negative ionization modes, leading to potential damage or contamination due to voltage discrepancies.
Innovation Solution
A mass spectrometer with a voltage controller that temporarily sets DC offset voltages to zero for a predetermined waiting time before switching between measurement modes, reducing voltage differences between electrodes and preventing electric discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If DC offset voltage is applied to electrodes for imparting collision energy to ions, then collision energy is effectively imparted to ions, but voltage discrepancy occurs during mode switching causing electric discharge between electrodes
Solution Approach 1:
The voltage controller temporarily sets the DC offset voltage to zero before switching between positive and negative ionization modes. This preliminary action of resetting voltage prevents voltage discrepancy and electric discharge during mode switching, while still allowing collision energy to be imparted when needed in stable operation modes
2Adaptability or versatility
If DC offset voltage polarity is switched during mode switching, then collision energy direction is adjusted for different ion types, but unintended electric discharge occurs between closely located electrodes
Solution Approach 1:
The voltage controller applies a counter-action by temporarily setting DC offset voltage to zero before polarity switching occurs. This preliminary anti-action neutralizes the voltage difference that would otherwise cause electric discharge, allowing safe mode switching between positive and negative ionization measurements
3Productivity
If voltage switching is performed rapidly for efficient mode switching, then measurement efficiency is improved, but voltage discrepancy causes electric discharge between electrodes
Solution Approach 1:
The voltage controller performs a preliminary voltage reset to zero before mode switching. This preliminary action takes a brief moment but prevents electric discharge, allowing rapid and safe mode switching by eliminating the harmful voltage discrepancy that would otherwise occur during fast transitions
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
Prevents unintended electric discharge between electrodes, thereby avoiding damage or contamination, and ensures safe and efficient switching between positive and negative ionization modes.
Implementation Method 1
DC voltages V1, V2 and V3 generated by adding different ion-converging DC voltages to a common DC offset voltage are applied to the three plate electrodes 171-173 forming the lens electrode 17, respectively
Implementation Method 2
An ion having a high amount of energy is introduced into the collision cell and is made to undergo dissociation through collision with the inert gas. This collision energy is given to the ion by a voltage difference between a DC voltage applied to an ion guide placed within the collision cell
Data Source
AI summary
In a tandem mass spectrometer, when the measurement mode is switched between a positive ion measurement mode and a negative ion measurement mode, a DC offset voltage applied to a lens electrode to impart collision energy to an ion is temporarily switched to 0V (S1). After being maintained at 0V for a predetermined waiting time (S2), the voltage is changed to a DC offset voltage corresponding to a measurement mode which is used after the switching operation (S3). By such an operation, the voltage difference between the neighboring plate electrodes among the plate electrodes (171, 172, 173) included in the lens electrode can be decreased as compared to the case where the polarity of the DC offset voltage is immediately switched. Consequently, unintended electric discharge between the neighboring electrodes can be prevented.