Mass Spectrometer Interleaved Acquisition Reduces Interscan Time
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Solution Overview
Problem
Current mass spectrometry techniques face limitations in reducing the interscan time between successive MRM transitions, which restricts the overall cycle time and measurement accuracy due to serial reconfiguration and ion transit times.
Innovation Solution
The method involves determining the time T based on ion transit times through the mass spectrometer components to allow simultaneous reconfiguration and transmission of ions for the second acquisition during the first dwell period, exploiting stored ion current to reduce interscan time without affecting the previous measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mass spectrometer is reconfigured to monitor a second transition after completing the first transition measurement, then the instrument can measure multiple different precursor-fragment ion transitions (MRM), but the interscan time cannot be reduced below the transit time of ions through the mass spectrometer
Solution Approach 1:
The first quadrupole mass filter is reconfigured for the second transition at time T1, before the first transition measurement is complete. This preliminary reconfiguration allows ions for the second transition to be transmitted during the interscan period, eliminating the need to wait for ion transit completion before switching configurations.
Solution Approach 2:
The patent introduces temporal interleaving of multiple transitions by operating the first quadrupole mass filter in a time-dependent manner. Different transitions are measured in an interleaved sequence rather than sequentially completing one transition before starting the next, effectively utilizing the ion transit time dimension to overlap measurements.
2Measurement precision
If the dwell time for each transition is increased to improve measurement sensitivity and accuracy, then more accurate ion current measurements can be obtained, but the cycle time increases and fewer transitions can be measured in a given time frame
Solution Approach 1:
The mass spectrometer maintains continuous ion transmission and measurement capability by overlapping the measurement windows of different transitions. The interleaved acquisition ensures that the ion current is continuously being measured for different transitions without idle periods, maximizing the utilization of available measurement time.
Solution Approach 2:
The first quadrupole mass filter dynamically switches between different transmission configurations at precisely timed intervals. The reconfiguration timing is optimized to allow sufficient ion transmission for each transition while enabling rapid switching between transitions, creating a dynamic measurement system that adapts to the ion transit characteristics.
Data Source
AI summary
A method of mass spectrometry is disclosed comprising passing ions through a first stage and a second stage of a mass spectrometer and monitoring a first ion acquisition for a first dwell time extending from a time T1 to a time T1+Tdwell1. The method further comprises reconfiguring the mass spectrometer or one or more components of the mass spectrometer to monitor a second ion acquisition and setting the first stage to transmit ions of the second ion acquisition at a time T, wherein T<T1+Tdwell1. The method further comprises monitoring the second ion acquisition for a second dwell time starting at a time T2, wherein T2>T1+Tdwell1 and determining the time T based on a known or calculated ion transit time through one or more regions or components of the mass spectrometer disposed downstream of the first stage.