ABSTRACT
This chapter discusses the theoretical and practical aspects of mass spectrometry that are relevant to separation science. J. J. Thomson is regarded as the father of mass spectrometry upon his discovery in 1897 of the electron and his subsequent determination of its mass to charge ratio. Prior to this, in 1886, E. Goldstien had discovered positively charged gas-phase ions, anode rays, from within a gas discharge tube. Electron ionization (EI) is performed by impacting an electron with some energy into the gas-phase molecule of interest. Chemical Ionization (CI) is a softer ionization technique than EI imparting less energy into the molecule. In principle, CI occurs by the transfer of energy from an interaction between an initial ion and the molecule of interest. Resolution is one of the defining characteristics of a mass spectrometer, and can be described as the ability to distinguish between ions differing in the quotient mass/charge by a small increment.
