Multipole Ion Trap RF AC Voltage Segmentation
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Solution Overview
Problem
Existing methods for simultaneously trapping ions of both positive and negative polarity in linear ion traps face challenges such as interference with adjacent spectrometer components and inefficient transfer due to unbalanced RF voltages, limiting their effectiveness.
Innovation Solution
Applying a combination of radio-frequency (RF) and alternating current (AC) voltages to multipole rod sets, with the AC voltage being of the same or lower frequency and in a single phase, to create a localized effective potential barrier that confines ions of both polarities within a single volume without extending into adjacent elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RF voltage is applied to the ends of the LIT to trap ions of both polarities, then ion containment is improved, but interference with adjacent spectrometer components increases
Solution Approach 1:
The patent divides the ion trapping function into two separate regions: the LIT for trapping ions of one polarity and the QIT for trapping ions of the opposite polarity. This segmentation allows each trap to operate independently with optimized RF voltages, preventing interference with adjacent components while maintaining reliable ion containment in both regions
Solution Approach 2:
The patent introduces an intermediary region between the LIT and QIT where ion transfer occurs. This intermediary space acts as a buffer zone that isolates the two trapped ion populations, allowing efficient ion transfer while preventing the RF fields from one trap from interfering with the other trap and adjacent spectrometer components
2Reliability
If unbalanced RF voltages are applied to rod sets to trap ions of both polarities, then ion containment is improved, but ion transfer efficiency deteriorates
Solution Approach 1:
The patent employs dynamic voltage switching between the LIT and QIT, where the RF voltages are alternated in a coordinated manner. This dynamic operation allows ions to be efficiently transferred from one trap to the other while maintaining stable containment during each phase, resolving the contradiction between containment reliability and transfer efficiency
Solution Approach 2:
The patent implements periodic alternation of RF voltages between the LIT and QIT at matched frequencies. This periodic action creates synchronized potential well oscillations that facilitate efficient ion transfer during the transition phases while maintaining stable ion containment during the holding phases, thereby achieving both reliable containment and high transfer efficiency
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 allows for improved containment and manipulation of ions of both positive and negative charges, enhancing the analytical capabilities of mass spectrometers by reducing interference and increasing the efficiency of ion transfer and reaction processes.
Implementation Method 1
providing a radio-frequency (RF) voltage to at least two of the electrodes; providing an alternating current (AC) voltage to the rod set in addition to the RF voltage
Implementation Method 2
simultaneously contain ions of both polarities by providing both radio-frequency (RF) and alternating current (AC) voltages
Data Source
AI summary
The applicants' teachings provide methods, systems, and apparatus useful in operating mass spectrometers and other devices incorporating multipole rod sets or other multi-electrode devices to simultaneously contain ions of both positive and negative charges through the simultaneous application to the rods or other electrodes of both radio-frequency (RF) and alternating (AC) currents.