Determination of Germanium in Nile Blue-12-Molybdogermanate-Polyvinyl Alcohol System
Li Zubi (Adult Education College ,Yunnan University, Kunming 650091)Xu Qiheng (Department of Chemistry. Yunnan University)
A sensitive spectrophotometric method for the determination of germanium using nile blue-12-molybdo-germanate (NB-GeMo) system in the aqueous solution of perchloric acid medium and in the presence of polyvinyl alcohol (PVA) has been proposed. The optimal condition for the quantitative formation of 12-molybdogermanic acid and its ion associate complex with nile blue was described. The apparent molar absorptivity of NB-GeMo is 9. 08 × 105 L ·mol-1 · cm-1at 605 nm. The ion associate complex is stable for at leaast 16 h. Beer's law is obeyed in the range of 0-4 μg/25 ml for Ge. The molar ratio of NB to GeMo in the complex was found to be 9 ' 1 by the equilibrium morving method and molar ratio method. The infrared spectrogram shows that perchlorate is the component part of the ion associate complex. The method has been used for the determination of germanium in actual samples with satisfactory results.