TOF Ion Guide Switching Between Zeno and Normal Pulsing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tandem mass spectrometry methods face challenges in dynamically switching between normal and Zeno pulsing modes without introducing delays, particularly in targeted acquisition methods where precise timing is crucial.
Innovation Solution
The system dynamically controls the ion guide and TOF mass analyzer to switch between normal and Zeno pulsing modes based on the intensity of product ions, maintaining constant TOF extraction pulse timing to avoid delays and saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Zeno pulsing mode is used to concentrate ion packets, then sensitivity is improved, but detector saturation occurs
Solution Approach 1:
The system dynamically switches between normal pulsing mode and Zeno pulsing mode based on real-time ion intensity measurements. When ion intensity is low, Zeno pulsing concentrates ion packets to enhance sensitivity. When ion intensity is high, normal pulsing is used to prevent detector saturation. This dynamic adaptation allows the system to optimize sensitivity while avoiding harmful saturation effects.
Solution Approach 2:
The pulsing mode parameter is changed based on ion intensity conditions. The system monitors product ion intensity and switches the pulsing mode accordingly: using Zeno pulsing (with ion packet concentration) when intensity is below a threshold, and normal pulsing (without concentration) when intensity exceeds the threshold. This parameter change resolves the contradiction by adapting the concentration effect to appropriate intensity levels.
2Measurement precision
If dynamic switching between pulsing modes is implemented, then sensitivity is optimized, but timing delays are introduced
Solution Approach 1:
The system performs preliminary monitoring of product ion intensity during the acquisition cycle and switches pulsing modes proactively based on predicted intensity levels. By anticipating when saturation might occur or when sensitivity enhancement is needed, the system switches modes in advance, minimizing timing delays and ensuring optimal detection conditions are maintained throughout the analysis.
3Quantity of substance
If normal pulsing mode is used, then linear dynamic range is maintained, but sensitivity is reduced
Solution Approach 1:
The system dynamically selects the pulsing mode based on real-time ion intensity conditions. Normal pulsing mode is used when ion intensity is high to maintain linear dynamic range and prevent saturation. Zeno pulsing mode is activated when ion intensity is low to enhance sensitivity through ion packet concentration. This dynamic selection allows the system to optimize for the appropriate parameter depending on current conditions.
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 sensitivity of tandem mass spectrometry without causing detector saturation, allowing for dynamic switching between pulsing modes to optimize ion detection and analysis.
Implementation Method 1
the same ion energy is applied to the ions over their travel through the ion guide to an extraction region disposed substantially along the guide axis irrespective of mass-to-charge ratio of the ions, and the ions are sequentially released with the same ion energy from the ion guide to provide for arrival of ions of substantially all released mass-to-charge ratios within the extraction region at substantially the same time and synchronized to coincide with a Time of Flight (TOF) extraction pulse of the mass analyzer
Implementation Method 2
The ion guide is adapted to provide an ion control field comprising a component for restraining movement of ions normal to the guide axis and comprising a component for controlling movement of the ions parallel the guide axis
Data Source
AI summary
Systems and methods are disclosed for dynamically switching an ion guide and a TOF mass analyzer between concentrating or not concentrating ions in a targeted acquisition. Product ions are ejected from the ion guide into the TOF mass analyzer and the intensity of a known product ion is measured at two or more time steps. The ion guide initially ejects product ions using a sequential or Zeno pulsing mode that concentrates product ions with different m/z values within the TOF mass analyzer at the same time. If the intensity of the product ion is increasing and greater than a threshold intensity, the ion guide switches to a continuous or normal pulsing mode that does not concentrate ions with different m/z values in the TOF mass analyzer at the same time. Similarly, if the intensity decreases below a threshold in continuous mode, the ion guide switches back to sequential mode.