title: Liquid chromatography determination of natural dyes in extracts from historical Scottish textiles excavated from peat bogs.
abstract: Textiles excavated from Scottish sites belonging now to the collections of the National Museums of Scotland, including seventeenth century textiles from peat bogs in the Scottish Highlands and Islands, were selected for analysis by high performance liquid chromatography with photodiode array detection (PDA HPLC) to detect whether any dyes remained and, if so, to identify their biological sources. Dye components were identified in 36 of the 81 samples analysed. Although it was not possible to identify the exact sources of the dyestuffs because of the wide-spread occurrence of these natural dyes components, the study has shown that textiles previously not thought to have been coloured had detectable traces of dye. Before the historical textiles were analyzed, an improved extraction procedure that combined the routine acid hydrolysis method with one using dimethylformamide (DMF) was applied. The DMF method enabled increased recovery of major flavonoid and anthraquinoid compounds, and very high efficiency of recovery of indigotin even in textiles with no colour visible, thereby complementing the acid hydrolysis method already in use. Extracts from historical thread samples were analysed by PDA HPLC using a reversed-phase gradient system comprising of a C18 column (150 mm x 4.6 mm i.d., 25 +/- 1 degrees C) with water, methanol and o-phosphoric acid at an eluent flow rate of 1.2 ml/min. A preliminary investigation to improve the detection limits further for a selection of natural dyes was made by comparing results from the 4.6mm internal diameter (i.d.) column with a narrow bore C18 column (2.1 mm i.d.). An increase in the detector response was observed for narrow-bore column proving its possibility of enhancement of sensitivity.
authors.affiliation: Department of Chemistry, Warsaw University, ul. Pasteura 1, 02-093 Warsaw, Poland. isurow@chem.uw.edu.pl
authors.forename: Izabella
authors.initials: I
authors.lastname: Surowiec
authors.forename: Anita
authors.initials: A
authors.lastname: Quye
authors.forename: Marek
authors.initials: M
authors.lastname: Trojanowicz
mesh_terms: D000818:Animals; D000880:Anthraquinones / Q000032:analysis; D005591:Chemical Fractionation / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004396:Coloring Agents / Q000032:analysis* / Q000266:history*; D004126:Dimethylformamide; D005419:Flavonoids / Q000032:analysis; D049669:History, 16th Century; D049670:History, 17th Century; D006801:Humans; D000432:Methanol; D012606:Scotland; D012987:Soil / Q000032:analysis; D013784:Textiles / Q000032:analysis* / Q000266:history; D014935:Wool / Q000737:chemistry
chemical_list: D000880:Anthraquinones; D004396:Coloring Agents; D005419:Flavonoids; D012987:Soil; D004126:Dimethylformamide; D000432:Methanol