title: [Structural analysis of unknown dyes detected in hajikami (ginger pickled in vinegar)].
abstract: Hajikami (ginger pickled in vinegar) is often used as a relish for grilled fish, and it often contains coloring agents. We detected Rose Bengal (R105) and two unknown dyes in some Hajikami by thin layer chromatography. In this study, we tried to characterize these unknown dyes by HPLC with photodiode array detection (PDA-HPLC), liquid chromatography/mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR). PDA-HPLC analysis showed that the spectra of the unknown dyes resembled that of R105, suggesting the molecular structures of these two dyes are similar to that of R105. Furthermore, LC/MS analysis suggested that the these dyes are R105 in which one or two iodines are replaced by hydrogen. Finally, the two dyes were determined by 1H-NMR and 13C-NMR to be 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran- 1 (3H),9'-[9H]xanthen]-3-one disodium salt and 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran-1(3H),9'[9H]xanthen]-3-one disodium salt.
authors.affiliation: Tokyo Metropolitan Institute of Public Health: 3-24-1, Hyakunin-cho, Shinjuku-ku, Tokyo 169-0073, Japan.
authors.forename: Fusako
authors.initials: F
authors.lastname: Ishikawa
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Oishi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Shindo
authors.forename: Masao
authors.initials: M
authors.lastname: Horie
authors.forename: Akiko
authors.initials: A
authors.lastname: Yasui
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Uehara
authors.forename: Shuzo
authors.initials: S
authors.lastname: Ogino
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D004396:Coloring Agents / Q000737:chemistry* / Q000302:isolation & purification; D005504:Food Analysis; D020939:Zingiber officinale / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D012395:Rose Bengal / Q000032:analysis
chemical_list: D004396:Coloring Agents; D012395:Rose Bengal