Time of Flight Mass Spectrometer Ion Coincidence Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Time of flight mass spectrometers face limitations in duty cycle and dynamic range when measuring targeted subsets of mass ranges, as conventional methods lack a systematic approach to prevent ion coincidence and intermixing during analysis.
Innovation Solution
A control system is implemented to apply extraction pulses to the acceleration electrode, determining a frequency or period that avoids ion coincidence by calculating the times of flight based on predetermined mass to charge ratio ranges, ensuring that ions with higher mass to charge ratios arrive after those with lower ratios, thereby improving duty cycle and dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional extraction pulse timing is used in time of flight mass spectrometry, then the mass range coverage is maintained, but the duty cycle and dynamic range are limited due to ion coincidence and intermixing
Solution Approach 1:
The control system predetermines the frequency or period of extraction pulses based on known mass to charge ratio ranges before ions are introduced. This preliminary calculation of optimal pulse timing prevents ion coincidence and intermixing at the detector, thereby improving duty cycle and dynamic range without requiring complex real-time adjustments during ion analysis
Solution Approach 2:
The invention changes the timing parameters (frequency or period) of extraction pulses based on the specific mass to charge ratio ranges being analyzed. By adjusting these parameters to match the expected ion arrival times, the system optimizes performance for targeted mass ranges while maintaining simplicity in the control architecture
2Productivity
If extraction pulses are applied at high frequency to improve duty cycle, then more ions can be analyzed per unit time, but ion coincidence occurs at the detector reducing measurement accuracy
Solution Approach 1:
The control system uses knowledge of the relationship between mass to charge ratio and time of flight to determine optimal extraction pulse frequencies. This feedback mechanism ensures that pulses are timed such that ions of different mass to charge ratios arrive at the detector at distinct times, preventing coincidence while maximizing the number of ions analyzed per unit time
Solution Approach 2:
Extraction pulses are applied periodically with a frequency or period that is specifically determined to avoid ion coincidence. This periodic timing, based on predetermined mass to charge ratio ranges, allows high ion throughput while maintaining clear separation of ion arrival times at the detector
3Measurement precision
If the mass range is restricted to targeted subsets for SIR or MRM experiments, then specificity and selectivity improve, but the duty cycle remains limited without optimized pulse timing
Solution Approach 1:
The control system applies extraction pulse timing optimization specifically tailored to the targeted mass to charge ratio ranges used in SIR or MRM experiments. This localized optimization for specific mass ranges improves duty cycle and sensitivity for those targeted measurements without compromising the specificity and selectivity that result from focusing on particular ions of interest
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 duty cycle and dynamic range of time of flight mass spectrometry by preventing ion coincidence, allowing for non-overlapping arrival times of ions with different mass to charge ratios, thereby improving measurement specificity and sensitivity.
Implementation Method 1
Time of flight mass spectrometers have been employed due to their high mass accuracy, resolution and duty cycle
Implementation Method 2
Time of flight mass analysers typically use a pusher or acceleration electrode to accelerate groups of ions into a time of flight region
Data Source
AI summary
There is provided a mass spectrometer comprising a time of flight mass analyzer comprising an acceleration electrode, a time of flight region and an ion detector, and a control system arranged and adapted (i) to apply a plurality of extraction pulses to said acceleration electrode in order to accelerate consecutive groups of ions into said time of flight region, wherein ions having a relatively high mass to charge ratio in a preceding group of ions arrive at said detector after ions having a relatively low mass to charge ratio in a subsequent group of ions, wherein ions within each consecutive group of ions have a mass to charge ratio within one or more predetermined, selected or otherwise known mass to charge ratio ranges, and (ii) to determine a frequency or period of said plurality of extraction pulses that will avoid coincidence of ions from said consecutive groups of ions at said ion detector, wherein said plurality of extraction pulses are applied at said determined frequency or period.