Mass Spectrometer Fragmentation Device Mode Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hybrid quadrupole-Time of Flight mass spectrometers have low duty cycles, making them unsuitable for applications requiring higher duty cycles, such as on-line chromatography, and struggle with efficiently screening samples for multiple compounds and confirming their presence due to low fragmentation efficiency.
Innovation Solution
A method involving a mass spectrometer with a fragmentation device that alternates between fragmentation and non-fragmentation modes to improve duty cycle, allowing for the detection of parent and fragment ions with similar elution or ion mobility drift times, thereby enhancing the screening and confirmation of known compounds in a sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional hybrid quadrupole-Time of Flight mass spectrometers are used to perform fragmentation analysis, then compound identification capability is improved, but duty cycle decreases significantly
Solution Approach 1:
The patent implements periodic switching between fragmentation and non-fragmentation modes in the collision cell. The method alternates between acquiring fragment ion spectra (for compound identification) and precursor ion spectra (for screening and quantification), thereby achieving both compound identification and maintaining high duty cycle through time-multiplexed operation
Solution Approach 2:
The collision cell operates in a dynamic manner by rapidly switching between two distinct operational states: fragmentation mode and non-fragmentation mode. This dynamic switching allows the system to adapt its function in real-time, optimizing both identification accuracy and analysis speed without requiring separate instruments
2Adaptability or versatility
If the number of compounds to be screened increases, then screening coverage is improved, but duty cycle decreases
Solution Approach 1:
The patent segments the analysis process into two distinct operational phases: screening mode (non-fragmentation) for rapid detection of multiple compounds, and confirmation mode (fragmentation) for verifying identified compounds. This segmentation allows efficient handling of large numbers of compounds by separating the screening and confirmation steps in time
Solution Approach 2:
The method performs preliminary screening using precursor ion detection in non-fragmentation mode before proceeding to confirmation analysis. This preliminary action identifies candidate compounds that require further verification, thereby reducing the overall analysis time by avoiding unnecessary fragmentation cycles for all compounds
3Measurement precision
If multiple fragment ions are monitored for compound confirmation, then identification accuracy is improved, but analysis time increases
Solution Approach 1:
The patent maintains continuous useful action by performing both precursor ion monitoring and fragment ion analysis in an interleaved, time-multiplexed manner. The continuous switching between fragmentation and non-fragmentation modes ensures that no data acquisition time is lost, as the system is constantly gathering useful information in both modes
4Reliability
If data is re-examined for co-eluting interferences, then measurement reliability is improved, but processing time increases
Solution Approach 1:
The method performs preliminary examination of both precursor and fragment ion data during the acquisition phase itself, rather than requiring separate post-processing steps. By continuously monitoring both ion types in interleaved cycles, the system proactively identifies potential co-eluting interferences during the analysis window
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 significantly improves the duty cycle and enables efficient screening and confirmation of compounds, allowing for simultaneous monitoring of multiple compounds and improved time alignment of precursor and product ions, enhancing the accuracy and efficiency of compound detection in complex samples.
Implementation Method 1
an orthogonal acceleration Time of Flight mass analyser
Implementation Method 2
orthogonal acceleration Time of Flight mass analyser
Implementation Method 3
parent ions generated from a sample are selected by a first mass filter/analyser and are then passed to a collision cell wherein they are fragmented by collisions with neutral gas molecules
Data Source
AI summary
A method of screening a sample for the presence of one or more known compounds of interest is disclosed. A fragmentation device is repeatedly switched between a fragmentation mode of operation and a non-fragmentation mode of operation. A determination is made whether a candidate parent ion of interest is present in a non-fragmentation data set and whether one or more corresponding fragment ions of interest are present in a fragmentation data set. A further determination is made to check if the candidate parent ion of interest and the one or more corresponding fragment ions of interest have substantially similar elution or retention times and/or ion mobility drift times.