Identification of the monobrominated derivative of Acid Red 52 (Food Red No. 106) in pickled vegetables.
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 (1)H-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.
a Physics and Chemistry Testing and Research Division , Yokohama City Institute of Public Health , 2-7-1 Tomiokahigashi, Kanazawa-ku, Yokohama, Kanagawa 236-0051 , Japan.
Naoki
N
Ochi
b Mechanical and Material Engineering Division , Kanagawa Industrial Technology Center , 705-1 Shimo-imaizumi, Ebina, Kanagawa 243-0435 , Japan.
Tetsuya
T
Okuda
b Mechanical and Material Engineering Division , Kanagawa Industrial Technology Center , 705-1 Shimo-imaizumi, Ebina, Kanagawa 243-0435 , Japan.
Hisashi
H
Fujii
D001391:Azo Compounds / Q000737:chemistry*; D004396:Coloring Agents / Q000032:analysis* / Q000138:chemical synthesis; D005505:Food Coloring Agents / Q000032:analysis* / Q000138:chemical synthesis; D015394:Molecular Structure; D009282:Naphthalenesulfonates / Q000737:chemistry*; D014675:Vegetables / Q000737:chemistry*
D001391:Azo Compounds; D004396:Coloring Agents; D005505:Food Coloring Agents; D009282:Naphthalenesulfonates; C069309:C.I. Acid Red 106
Acid Red 52; Food Red No. 106; monobrominated derivative; unknown dye