Multiplexed Precursor Ion Selection in Mass Spectrometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional high throughput quantitative mass spectrometry analysis using multiple reaction monitoring (MRM) faces a tradeoff between the overall duty cycle of the data collection process and the signal-to-noise ratio (S/N) of the quantitative data, where improving one aspect adversely affects the other.
Innovation Solution
A system utilizing an electrical field potential barrier for multiplexed precursor ion selection and transmission, where a processor applies alternating current (AC) voltage frequencies to resonate and direct current (DC) voltage to transmit multiple precursor ions simultaneously, allowing for improved duty cycle without reducing signal-to-noise ratio, using an ion source, mass isolator, and processor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the analysis time of each target precursor ion is increased to achieve a certain signal-to-noise ratio, then the signal-to-noise ratio is improved, but the overall duty cycle of the data collection process increases (worsens)
Solution Approach 1:
The patent applies periodic AC voltage at specific resonant frequencies to the quadrupole rods to selectively transmit multiple precursor ions through the barrier electrode. By using periodic resonant excitation at different frequencies for different ion species, the system achieves multiplexed transmission without serial isolation, resolving the tradeoff between signal-to-noise ratio and duty cycle
Solution Approach 2:
The patent combines multiple precursor ion transmission events into a single simultaneous operation by using a barrier electrode with multiple resonant frequency channels. Instead of isolating and transmitting ions sequentially, the system merges multiple ion species into one multiplexed transmission event, improving duty cycle while maintaining signal-to-noise ratio
2Duration of action of moving object
If the analysis time of each target precursor ion is decreased to collect quantitative data across a narrow liquid chromatography peak, then the data collection across narrow peaks is improved, but the signal-to-noise ratio of the quantitative data is reduced
Solution Approach 1:
The system uses periodic resonant excitation at multiple frequencies simultaneously to transmit multiple precursor ions through the barrier electrode. This periodic action at resonant frequencies enables rapid sequential transmission of different ion species without requiring extended analysis time for each ion, maintaining signal-to-noise ratio while reducing overall analysis time
Solution Approach 2:
The barrier electrode maintains continuous operation by rapidly switching between different resonant frequencies to transmit different precursor ions. This continuous multiplexed transmission eliminates idle time between ion analysis events, allowing the system to collect data across narrow chromatography peaks without sacrificing signal-to-noise ratio
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 enables simultaneous selection and transmission of multiple precursor ions without compromising the signal-to-noise ratio, thereby optimizing the duty cycle of the data collection process.
Implementation Method 1
applying a direct current (DC) voltage to the barrier electrode lens relative to the rods of the selection region and rods of the transmission region in order to create an electric field potential barrier
Implementation Method 2
applying two or more different alternating current (AC) voltage frequencies to the rods of the selection region in order to resonate the two or more different precursor ions from the beam of ions
Data Source
AI summary
Systems and methods for identifying precursor ions of product ions from combined product ion spectra are provided. N precursor ions are selected. N groups of the N precursor ions are created. The tandem mass spectrometer is instructed to perform multiplexed precursor ion selection on the continuous beam of ions, fragment each of the N−1 precursor ions, and measure the intensities of the product ions, producing N product ion spectra. A heat map is plotted, producing N heat maps. The N product ion spectra are combined into a combined product ion spectrum. A corresponding precursor ion of a peak is identified by finding a heat map of the N heat maps that does not have data for the mass of the peak and determining that a precursor ion of the N precursor ions that is not included in a group that produced the heat map is the corresponding precursor ion.