Multiplexing in Multi-Reflecting TOF MS

Abstract

The paper presents an overview of original inventions, development and experimental results by the group of authors in the area of multi-reflecting time-of-flight mass spectrometry with Folded Flight Path (FFP ® ) (MR-TOFMS) with main focus on multiplexing methods for improving the analysis throughput, i.e. the amount of information per time unit. MR-TOF provides panoramic spectra (virtue of TOFMS), while significantly enhancing resolving power, thus, providing yet more information. Resolving power R=500,000 is demonstrated to resolve isobars and to improve mass accuracy to sub-ppm level. Encoded Frequent Pulsing (EFP TM ) method improves sensitivity, expands dynamic range and opens multiple incarnations of parallel and fast tandem methods of analysis based on using ion traps, TOFMS and ion mobility for rapid and lossless parent ion separations.

Genetic algorithm parallel optimization of a new high mass resolution planar electrostatic ion trap mass analyzer

“…Individuals are evaluated from the calculation of the fitness according to eqn (8) or (9), and the GA maximized the fitnesses through successive rounds of breedings so as to reduce the HTD max or HZ max . m denotes the population size; p denotes the individual index.…”

“…(1) in the first round, m chromosomes were initialized with random genes (i.e., the voltages on the electrodes to be searched are encoded to form chromosomes), and each chromosome consisted of four genes V 4 , V 5 , V 6 and V 7 ; (2) firstgeneration populations were created, with m chromosomes forming m individuals; (3) the trajectory of each ion in the test ion group was simulated separately and the "fitness" of each individual was calculated using by eqn (8) or (9).…”

“…7 However, the performance of such TOF mass analyzers is limited by many aspects, such as high time aberrations of electrostatic sectors, narrow mass ranges in looped schemes, and ion losses due to ion packet divergence. 8 Fourier transform mass spectrometry (FTMS) is an alternative way of achieving super high mass resolution, and so far it has achieved baseline separation of ions with mass differences of less than one electron mass, and also gives the highest mass accuracy (mass errors down to a few ppb (ref. 9)).…”

Novel Hybrid Quadrupole-Multireflecting Time-of-Flight Mass Spectrometry System

“…When utilizing an OA pulse cycle period of 2 ms, the sampling duty cycle of the analyzer is limited to ∼0.1–0.2% if we use the classical definition . To recover the sampling duty cycle, Encoded Frequent Pushing (EFP) ,, is used with a 128 pulse pattern, significantly improving the sampling duty cycle to greater than 10%. This 128-fold increase in sensitivity improves ion statistics and extends the lower end of the dynamic range of the achievable sub-ppm mass accuracy on this analyzer .…”

“…In particular, an MR-TOF with planar, gridless mirrors has shown significant utility in GC-MS applications . In analyzers of this type, periodic lenses are employed to mitigate ion beam divergence and control overall flight length, which has been extended up to 100 m and R m up to 500 000 fwhm …”