Single-Ion Trap Control in Charge Detection Mass Spectrometry
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Solution Overview
Problem
Charge detection mass spectrometry (CDMS) techniques face inefficiencies in determining the number of ions present in an ion trap, leading to wasted time and contaminated signals due to the presence of zero or multiple ions during trapping events, which affects the accuracy and throughput of mass spectrometry measurements.
Innovation Solution
A method and device for CDMS that monitor detector signals in real-time to determine the number of ions during ion trapping events, allowing for early termination or adjustment of trapping events to ensure only a single ion is analyzed, using ion trap geometry and control circuitry to eject excess ions and attenuate ion beams to control ion flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mass spectrometry methods are used to determine ion mass, then multiple charge states can be resolved, but the process becomes time-consuming and less accurate due to the need to resolve multiple charge states
Solution Approach 1:
The measurement process is segmented into two independent simultaneous measurements: one for mass-to-charge ratio (m/z) and one for charge (z). By separating the determination of mass and charge into distinct measurement pathways, the system avoids the time-consuming process of resolving multiple charge states sequentially, achieving both high accuracy and fast throughput.
Solution Approach 2:
The system performs measurements on individual ions rather than requiring complete resolution of all charge states in a population. By focusing measurement resources on single ions and using statistical methods to determine charge, the system achieves accurate mass measurements without the excessive time required for full charge state resolution.
2Quantity of substance
If ion trapping events are extended to capture more ions, then signal strength increases, but space charge effects increase causing signal contamination and reduced accuracy
Solution Approach 1:
The system continuously monitors the ion trap for the presence and number of ions during the trapping event. When the detector identifies multiple ions or space charge effects, it provides feedback to terminate the trapping event early or eject excess ions. This real-time feedback mechanism maintains optimal ion numbers, preventing space charge contamination while maximizing signal strength.
Solution Approach 2:
The ion trapping process is made dynamic rather than static. The system can adjust trapping duration, terminate events early, and eject ions based on real-time conditions. This dynamic control allows the system to optimize the number of ions in the trap for each measurement, adapting to prevent space charge effects while maintaining strong signals.
3Measurement precision
If ion beam intensity is increased to improve signal detection, then detection sensitivity improves, but the likelihood of multiple ions being present increases causing measurement contamination
Solution Approach 1:
The system uses the detector itself to monitor and control the ion population in real-time. The detector serves dual purposes: measuring ion presence and controlling the measurement process by triggering termination or ejection when multiple ions are detected. This self-service approach ensures high detection sensitivity while maintaining reliability through automatic quality control.
Solution Approach 2:
The system performs preliminary checks during the ion trapping event to determine the number of ions present before completing the measurement. By detecting multiple ions early in the trapping process, the system can terminate or adjust the event before contamination occurs, ensuring reliable single-ion measurements while maintaining high detection sensitivity.
4Measurement precision
If real-time monitoring and control of ion trapping events is implemented, then measurement accuracy improves, but device complexity increases due to additional control circuitry and monitoring requirements
Solution Approach 1:
The detector serves multiple functions: it detects ion presence, determines ion number, triggers termination events, and controls ion ejection. By making the detector a multi-functional control center, the system achieves high measurement precision without adding separate monitoring and control devices, thereby limiting the increase in device complexity.
Solution Approach 2:
The monitoring and control functions are merged with the existing detector and ion trap operations. Rather than adding separate real-time monitoring systems and control mechanisms, the invention integrates these functions into the existing measurement apparatus, achieving accurate ion counting while minimizing additional complexity through functional integration.
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 enhances the throughput and accuracy of CDMS by dynamically controlling ion trapping events, reducing space charge effects and improving the quality of mass spectrometry measurements by ensuring only a single ion is analyzed, thereby increasing the rate of generating spectra and minimizing interference.
Implementation Method 1
a charge detector within the ion trap for determining a charge for the one or more ions to be analysed
Data Source
AI summary
Disclosed herein are various methods and apparatus for performing charge detection mass spectrometry (CDMS). In particular, techniques are disclosed for monitoring a detector signal from a CDMS device to determine how many ions are present in the ion trap (10) of the CDMS device. For example, if no ions are present the measurement can then be terminated early. Similarly, if more than one ion is present, the measurement can be terminated early, or ions can be removed from the trap (10) until only a single ion remains. Techniques are also provided for increasing the probability of there being a single ion in the trap (10). A technique for attenuating an ion beam is also provided.