The Practical Analysis of High-Purity Chemicals. VI. Emission Spectrographic Analysis of High-Purity Acids

The spectrographic analysis of volatile acids in a high-purity form is reviewed and a procedure presented that involves evaporation of a 100-g sample under temperature controlled contamination-free conditions and emission spectrography using dc-arc excitation under controlled atmosphere. In the evaporation, graphite (10 mg) is added as a collector, sulfuric acid to convert to less volatile sulfates (with acetic, hydrochloric, and nitric acids), and also mannitol to retain boron (with hydrochloric and hydrofluoric acids). Indium is added as a internal standard. Spectra are examined for 33 elements against a multielement standard in graphite containing indium as an internal standard. For the concurrent analysis of three samples, the elapsed time is 4–10 h and the actual working time 3–5 h. Recovery studies are reported as well as the use of the procedure in the assessment of the leaching of borosilicate glass by concentrated mineral acids.