The work is devoted to the investigation and development of innovative plasma diagnostics method based on mutual application of plasma immersion and time-of-flight approaches for ion charge state and mass measurements. It is experimentally demonstrated that despite the presence of long tails in ion current waveform measured by Faraday cup, there is a way to increase the spectrometer resolution by several times. The current pulse FWHM equal to 170ns was reached, that gave a possibility to use this approach for ion charge state and mass measurement for plasma with any element of the Periodic Table.