Improvement of Analytical Procedures for the Determination of Components in Etching Solutions

摘要

An improvement in the volumetric methods for the determination sulfuric and hydrofluoric acids in etching solutions has been made by using: mixed indicator Tashibo (methylene blue + methyl red), when the mixture is titrated with standard solution NaOH for the determination of HF acid. For the determination of H2SO4 acid, sulfate ion is titrated with standard solution BaCl2 with nitrosulfonaso III, as indicator. Impurities (iron and titanium) have been precipitated from the acid solutions by NH4OH, as hydroxides of these elements. Precipitate is dissolved in HC1 (1:1) and iron and titanium can be determined by photometric methods.