Hisashi Fujii

Cleaning of Ge(110) Surfaces Using an Excimer Lamp.

The formation of a GeO2 overlayer on a Ge sample surface in the air and subsequent removal of the overlayer in ultrahigh vacuum is a newly developed method of cleaning Ge surfaces. Using an excimer lamp as an ultraviolet light source for the oxidation, we attempted to clean Ge(110), (111) and (100) surfaces and observed that well-reconstructed structures characteristic of clean surfaces appeared on the surfaces. Reflection high-energy electron diffraction observations immediately after the removal of the oxide overlayer suggest that the interface of the oxide overlayer and Ge(110) substrate is rough, but it is relatively smooth in the cases of Ge(111) and Ge(100) substrates.

Identification of the monobrominated derivative of Acid Red 52 (Food Red No. 106) in pickled vegetables

ABSTRACT Two unknown dyes (purple and purplish-red) were detected by TLC in two pickled vegetable (sakura-zuke daikon) samples containing Acid Red 52 (AR) and New Coccine as food colorants. HPLC with diode-array detection and LC/MS analyses suggested that the purple dye is monobrominated AR and the purplish-red dye is its N-desethyl derivative, which would be generated mainly during sample preparation. For the identification of the purple dye, a reference compound was prepared by bromination of AR followed by isolation of the monobrominated AR, the structure of which was elucidated as 4′-brominated AR (4′BrAR) by LC/ToF-MS and 1H-NMR spectroscopy. The purple dye was confirmed as 4′BrAR by comparison of its retention time, ultraviolet-visible spectrum and mass spectrum with those of the prepared reference compound. To our knowledge, this is the first report of the detection of 4′BrAR in foods.