FIELD: methods of monitoring content of oxygen in materials containing metal used in electronic devices. SUBSTANCE: proposed method includes deoxidation of material containing metal used in electronic devices: tantalum, niobium and their alloys; leaching of material is performed in acid leaching solution at temperature below room temperature. According to one version, acid leaching solution is prepared and cooled to temperature below room temperature before leaching the deoxidized material containing metal used in electronic devices. Proposed method reduces concentration of oxygen and fluoride in materials containing metal used in electronic devices since acid leaching performed at reduced temperature requires lesser amount of oxygen for preset amount of leaching acid, such as hydrofluoric acid. EFFECT: reduction of content of oxygen in materials containing valve metals or maintenance of content of metals at the same level; improved electrical properties of capacitors; reduced plasticity of products or articles. 27 cl, 6 tbl, 6 ex
