TY - JOUR
T1 - Removal of natural organic dyes from wool-implications for ancient textile provenance studies.
AU - Frei, Karin Margarita
AU - Vanden Berghe, Ina
AU - Frei, Robert
AU - Mannering, Ulla
AU - Lyngstrøm, Henriette Syrach
PY - 2010/9
Y1 - 2010/9
N2 - Ancient wool textiles recovered from archaeological sites are in many cases originally dyed with natural organic dyestuffs from vegetable sources. These include among others woad (Isatis tinctoria L.), weld (Reseda luteola L.), and madder (Rubia tinctorum L.). These dyestuffs could be a threat to the use of the strontium isotopic system as a tracer for provenance studies of ancient wool, because they could potentially contaminate the signature of the textile's raw material. We present a novel method which allows for efficient removal of organic dyestuffs in wool prior to strontium isotopic analysis. Our method is based on an oxidative release of the dyestuff constituents by ammonium peroxodisulfate [(NH4)2S2O8] solution, combined with hydrofluoric acid (HF) that has shown to effectively remove/dissolve adhering dust micro-particles. Our multi-analytical results show that such a pretreatment is capable of removing >98% of the originally present organic dyestuffs without significantly destroying the wool structure. The strontium isotopic ratios of the residual wool fraction after the application of the pretreatment are sensitive to the origin and, therefore, can be used as tracers for the provenance of the raw material. We propose to apply this method to ancient wool textiles in which positive identification of organic dyestuff constituents by High Performance Liquid Chromatography (HPLC) was made.
AB - Ancient wool textiles recovered from archaeological sites are in many cases originally dyed with natural organic dyestuffs from vegetable sources. These include among others woad (Isatis tinctoria L.), weld (Reseda luteola L.), and madder (Rubia tinctorum L.). These dyestuffs could be a threat to the use of the strontium isotopic system as a tracer for provenance studies of ancient wool, because they could potentially contaminate the signature of the textile's raw material. We present a novel method which allows for efficient removal of organic dyestuffs in wool prior to strontium isotopic analysis. Our method is based on an oxidative release of the dyestuff constituents by ammonium peroxodisulfate [(NH4)2S2O8] solution, combined with hydrofluoric acid (HF) that has shown to effectively remove/dissolve adhering dust micro-particles. Our multi-analytical results show that such a pretreatment is capable of removing >98% of the originally present organic dyestuffs without significantly destroying the wool structure. The strontium isotopic ratios of the residual wool fraction after the application of the pretreatment are sensitive to the origin and, therefore, can be used as tracers for the provenance of the raw material. We propose to apply this method to ancient wool textiles in which positive identification of organic dyestuff constituents by High Performance Liquid Chromatography (HPLC) was made.
U2 - 10.1016/j.jas.2010.02.012
DO - 10.1016/j.jas.2010.02.012
M3 - Journal article
SN - 0305-4403
VL - 37
SP - 2136
EP - 2145
JO - Journal of Archaeological Science
JF - Journal of Archaeological Science
ER -