Pulse String Configuration for Accurate EFP ToF Decoding
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Solution Overview
Problem
Traditional Time of Flight (ToF) mass spectrometry with Encoded Frequent Pulsing (EFP) schemes face challenges in accurately demultiplexing multiplexed ion signals due to overlapping pulses, leading to potential loss of useful data and reduced accuracy in mass spectral data decoding.
Innovation Solution
A method is developed to configure a string of pulses by calculating and optimizing the span intervals and degree of overlap, uniformity, and objective function F, which involves reconfiguring pulse times to minimize overlap and maximize the objective function F, thereby improving the quality of demultiplexed data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ions are pulsed into the ToF mass analyser at a relatively high rate using EFP, then the duty cycle is increased, but the accuracy of decoding mass spectral data is reduced due to temporal overlap of ions from different pulses
Solution Approach 1:
The pulse string is segmented into N individual pulses with specifically optimized time intervals. By dividing the pulse sequence into discrete, optimally spaced segments, the method reduces temporal overlap between ions from different pulses while maintaining high pulsing rates, thus improving decoding accuracy without sacrificing duty cycle
Solution Approach 2:
The time intervals between pulses (span intervals) are optimized as a key parameter. By calculating and adjusting the span intervals Δtn(k) between each pulse and every other pulse in the string, the method finds optimal parameter values that minimize overlap while maintaining high pulsing frequency, resolving the contradiction between productivity and measurement precision
2Ease of manufacture
If the span intervals between pulses are not optimized, then the EFP acquisition is simpler to implement, but the quality of demultiplexed data is reduced due to increased overlap
Solution Approach 1:
The span intervals between pulses are pre-calculated and optimized before the actual EFP acquisition. By performing this optimization step in advance, the method establishes optimal pulse timing parameters that maximize data quality, while the actual acquisition process remains straightforward using these pre-determined parameters
Solution Approach 2:
The method includes automated calculation of the objective function F and iterative reconfiguring of pulse times to optimize the span intervals. This self-optimizing process automatically determines the optimal pulse configuration without requiring manual intervention, maintaining ease of implementation while achieving high data quality
Data Source
AI summary
A method of configuring a string of pulses for an encoded frequent pulsing (EFP) acquisition, comprising: (a) generating a string containing N pulses, each pulse occurring at a respective time tn, the string of length T, wherein in use the string of pulses is repeated to create a stream of pulses; (b) calculating the respective span intervals Δtn(k) between each pulse and every other pulse in the string, wherein k is the number of pulses in the span interval Δtn(k) (k being between 1 and N); (c) determining the degree of overlap D of the calculated span intervals Δtn by calculating the relative difference δΔt therebetween; (d) calculating the degree of uniformity S of the string of pulses; (e) calculating an objective function F=S−D for the string of pulses; (f) reconfiguring the string to alter the time tn of at least one pulse in the string; (g) calculating the objective function F′ for the reconfigured string and, if F′ is higher than F, adopting the reconfigured string.