title: Discovery and structural elucidation of the illegal azo dye Basic Red 46 in sumac spice.
abstract: An unknown red dye was discovered in a sumac spice sample during routine analysis for Sudan dyes. LC-DAD and LC-MS/MS did not reveal the identity of the red substance. Nevertheless, using LC-high-resolution MS and isotope ratio comparisons the structure was identified as Basic Red 46. The identity of the dye was further confirmed by comparison with a commercial hair-staining product and two textile dye formulations containing Basic Red 46. Analogous to the Sudan dyes, Basic Red 46 is an azo dye. However, some of the sample clean-up methodology utilised for the analysis of Sudan dyes in food prevents its successful detection. In contrast to the Sudan dyes, Basic Red 46 is a cation. Its cationic properties make it bind strongly to gel permeation columns and silica solid-phase extraction cartridges and prevent elution with standard eluents. This is the first report of Basic Red 46 in food. The structure elucidation of this compound as well as the disadvantages of analytical methods focusing on a narrow group of targeted analytes are discussed.
authors.affiliation: Official Food Control Authority of tCanton of Thurgau (Kantonales Laboratorium Thurgau), Spannerstrasse 20, CH-8510 Frauenfeld, Switzerland. juerg.ruf@tg.ch
authors.forename: J
authors.initials: J
authors.lastname: Ruf
authors.forename: P
authors.initials: P
authors.lastname: Walter
authors.forename: H
authors.initials: H
authors.lastname: Kandler
authors.forename: A
authors.initials: A
authors.lastname: Kaufmann
mesh_terms: D001391:Azo Compounds / Q000737:chemistry* / Q000592:standards; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000737:chemistry* / Q000592:standards; D015394:Molecular Structure; D012015:Reference Standards; D029045:Rhus / Q000737:chemistry*; D052616:Solid Phase Extraction; D017365:Spices / Q000032:analysis*; D053719:Tandem Mass Spectrometry
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; C050846:basic red 46