Abstract: The proposed method is related to the field of technical physics, in particular, to spectral methods for determining elemental composition of liquid media using an electric discharge in the liquid as a source of spectra. The method can be implemented in devices for determining elemental composition of liquid media. The areas of application include water treatment systems at public water supply facilities, nuclear and thermal power industries, chemical industry, food industry processes (for water quality control), environment monitoring, etc. The technical result of the invention is higher stability and reproducibility of measurement results and better long-term operation reliability of the device.