CS2 CHARGE-EXCHANGE AS A LOW-ENERGY IONIZATION TECHNIQUE FOR HYDROCARBON CHARACTERIZATION

CS2.+ ions formed under low-energy electron ionization conditions readily undergo charge-exchange reactions with hydrocarbons having ionization potential less than 9.5 eV. CS2 charge exchange (CS2/CE) has many advantages over low-voltage electron-impact ionization (LV/EI) in the characterization of hydrocarbons. Small variations in electron beam energies do not affect the relative yields of the molecular ions. Higher sensitivities in CS2/CE over LV/EI facilitate high-resolution accurate mass measurements. Uniform sensitivities over a wide range of compound types eliminate the need for calibration compounds for the quantitative determination of the components In a hydrocarbon mixture.