Ion Guide Bandpass Extraction for TOF Sensitivity Enhancement
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Solution Overview
Problem
Current methods for mass selective ion extraction in time-of-flight (TOF) mass spectrometry face inefficiencies, particularly in handling broad m/z ranges and protein analysis, due to issues like ion loss, collisional dissociation, and the need for additional cooling devices, which affect sensitivity and accuracy.
Innovation Solution
A system using a multipole rod set and lens electrode with judiciously applied radial RF and DC voltages, along with axial AC and DC voltages, enables bandpass mass range extraction without AC excitation, allowing continuous ion transmission and avoiding ion loss, collisional dissociation, and the need for cooling devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mass selective extraction is performed using conventional CID methods in an ion guide, then ion fragmentation is achieved, but posttranslational modifications are lost and sensitivity is reduced
Solution Approach 1:
The patent extracts only the necessary function of mass selective ion extraction from the ion guide, separating it from the fragmentation function. By using the ion guide solely for bandpass filtering and extracting ions to the TOF analyzer, the harmful collisional dissociation that causes loss of posttranslational modifications is eliminated while still achieving effective ion fragmentation through the TOF analysis process.
2Quantity of substance
If AC excitation is used for mass selective extraction, then ions can be bunched in the acceleration region, but additional cooling devices are required and device complexity increases
Solution Approach 1:
The patent implements continuous bandpass filtering of ions through the ion guide without interruption for cooling cycles. The ion guide continuously transmits ions within the selected m/z range to the TOF analyzer, eliminating the need for periodic cooling devices while maintaining effective ion bunching and transmission efficiency throughout the analysis process.
3Adaptability or versatility
If broad m/z range ions are transmitted through the ion guide, then comprehensive mass spectra can be recorded, but ion loss increases and transmission efficiency decreases
Solution Approach 1:
The patent dynamically adjusts the bandpass filtering parameters of the ion guide to match the specific m/z range of interest for each analysis. By making the transmission window adaptive rather than fixed, the system can optimize ion transmission efficiency for different mass ranges while maintaining comprehensive coverage capabilities, effectively resolving the contradiction between broad range capability and transmission 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 enhances the sensitivity of TOF mass spectrometry by enabling efficient bandpass filtering of ions, maintaining high sensitivity and accuracy across a wide m/z range without ion loss or secondary dissociation, and improving protein analysis by preserving posttranslational modifications.
Implementation Method 1
a radial dipole DC voltage is applied to a multipole rod set of an ion guide and an axial trapping AC voltage is simultaneously applied to a lens electrode of the ion guide in order to extract a bandpass mass range of ions trapped in the multipole rod set
Implementation Method 2
selecting an axial barrier potential to selectively extract ions having an m/z ratio less than a threshold from the first rod set into the second rod set
Data Source
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AI summary
A multipole rod set of an ion guide is adapted to receive a radial RF trapping voltage and a radial dipole direct current DC voltage. A lens electrode of the ion guide is positioned at one end of the multipole rod set to extract ions from the multipole rod set and adapted to receive an axial trapping AC voltage and a DC voltage. A radial dipole DC voltage is applied to the multipole rod set and an axial trapping AC voltage is simultaneously applied to a lens electrode in order to extract a bandpass mass range of ions trapped in the multipole rod set. Alternatively, a radial RF trapping voltage amplitude is applied to the multipole rod set and an axial trapping AC voltage is simultaneously applied to the lens electrode in order to extract a bandpass mass range of ions trapped in the multipole rod set.