Shin-ichi Hasegawa

The separation of aluminum(III) ions from the aqueous solution on membrane filter using Alizarin Yellow R

The membrane filtration was examined as an effective and selective method for collection of Al(III) ions from aqueous solutions using Alizarin Yellow R, one of a pH-indicator, as a precipitating reagent. For preparation of aqueous solutions without precipitate or turbidity, a non-ionic surfactant, Triton X-100, was used as a solubilizing reagent for insoluble materials. Three metal ions, Al(III), V(III) and Cu(II) ions, were able to be collected as yellow-orange precipitates from aqueous solutions controlled in a range of pH 4-7, pH 4-9, and pH 5.5-12, respectively, on a membrane filter by filtration under suction. Hydrogen peroxide and o-phenanthroline were found to be capable of masking V(III) and Cu(II) ions in a range of pH 5.5-8 in which Al(III) ions were collected. This membrane filtration was applied to selective separation and determination of Al(III) ions in tap water.

Component analyses of silver brazing filler metals by inductively coupled plasma atomic emission spectrometry: a collaborative study for standardization

A collaborative determination of the major components of silver brazing filler metals (Ag–Cu–Zn–Cd, Ag–Cu–Zn–Ni, and Ag–Cu–Zn–Sn alloys) by inductively coupled plasma atomic emission spectrometry (ICP-AES) was conducted. The classical wet methods of gravimetry and titrimetry were also investigated for comparison, most of which are provided by Japanese Industrial Standards (JIS). Results of instrumental and classical analyses using a simple dissolution procedure with nitric acid showed excellent trueness and precision amongst all laboratories and for all alloys except those containing tin. The tin-containing alloy had to be dissolved, suppressing precipitation of the sparingly soluble hydrous tin(IV) oxide. Dissolution with mixtures of nitric and sulfuric acid gave the most satisfactory results without precipitation, thus enabling an accurate determination that favourably compared to the classical wet results. Finally we have evaluated the ICP-AES method and a hybrid method with gravimetry and ICP-AES according to the precision required, and found them to be suitable for standardization.