We have investigated the hydration properties of lithium complexes of methyladenines (3-methyladenine; 3MA, 7-methyladenine; 7MA, 9-methyladenine; 9MA) using a quadrupole ion trap (QIT) mass spectrometer. Methyladenines complexed with a lithium cation were introduced into the vacuum system using electrospray ionization (ESI) and were isolated using MS/MS to react with water molecules within the quadrupole ion trap (QIT). The reaction time changed from 0 to 5 seconds, and the mass spectra after the reaction were recorded as a function of the reaction time. The decay curve of each methyladenine was obtained by measuring the fraction of ion intensity of [M+Li]+ (156m/z) over the total intensity of [M+Li]+ and [M+Li+H2O]+ (174m/z). The decay curves of lithium complexes of 3MA, 7MA, and 9MA showed distinct values in the decay time constants and the non-reacted fraction determined by the asymptote of hydration decay curve. We will discuss the differences in hydration dynamics of different methyladenine complexes with a lithium cation based on the different hydration decay time constants and fractions of non-reacted species.