Theoretical study of the impact of ion acceleration parameters on the mass resolving power in linear MALDI time-of-flight mass spectrometry

This work examines how ion acceleration parameters affect the mass resolving power (R_m) of linear time-of-flight (TOF) mass spectrometry (MS). Ion acceleration parameters have been considered as playing a minor role in determining the R_m in TOF MS. Based on results in two-dimensional topological space calculated in this work, we demonstrate that the length and electrical potential of the ion acceleration region critically affect R_m. The flight-time distribution of ions of m/z 3000 in a 3-m long linear TOF mass spectrometer is analyzed using the coupled space-velocity focusing method. Big data analysis reveals that four types of flight-time distribution are available by adjusting ion acceleration length. The coefficients in the equation of flight-time spread can be used to predict the best length for achieving highest performance. The results show an 18-fold increase in R_m when increasing the length of the ion acceleration region by a factor of ∼35 with respect to conventional design. Adjusting ion extraction parameters cannot provide the same magnitude of improvement. Correlation between R_m and critical experimental parameters are discussed.