The possibility of successfully applying a common GC-MS procedure for identification in one step all type of dyes from plants of unknown origin and from historical objects is particularly attractive due to the high separation efficiency of the capillary columns, the MS detection sensitivity and the reproducibility of results. In this work, GC-MS analysis, previously and successfully used for characterization of anthraquinones, flavonoids and tannins from plant extracts and historical samples, has been tested on indigoid dyestuffs. An analytical procedure based on silylating agent N,O-bis-(trimethylsilyl)-trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS), was applied on pure molecules of indigotin and indirubin and on plant extracts of Indigofera tinctoria L. and Isatis tintoria L. Preliminary tests have been done to establish the chromatographic conditions and the derivatization amounts most suitable for the simultaneous detection of indigoid molecules and of the other natural compounds, such as fatty acids, carboxylic acids and sugars, contained within the plant extracts. In order to assess the capacity and the sensitivity of the analytical procedure in the typical archaeometric applications, wool samples dyed in laboratory with indigo were analysed mimicking the sample amounts typically available with historical objects. The EI spectra of main silylated derivatives of indigoid molecules obtained in this way constitute the necessary data set for the characterization of natural extracts and historical works of art. Subsequently the procedure has been applied on historical samples for the detection of indigo and of other dyestuffs eventually contained in samples. Additional information, useful for restoration and preservation of works of art, could be also obtained on the nature of stains and smudges present on the sampled textile material. The GC-MS method turns out to be an efficient and fast analytical tool also for the identification of natural indigo in plants and textiles artefacts, providing results complementary to those coming from HPLC.
Identification of natural indigo in historical textiles by GC-MS
DEGANI, LAURA;RIEDO, CHIARA;CHIANTORE, Oscar
2015-01-01
Abstract
The possibility of successfully applying a common GC-MS procedure for identification in one step all type of dyes from plants of unknown origin and from historical objects is particularly attractive due to the high separation efficiency of the capillary columns, the MS detection sensitivity and the reproducibility of results. In this work, GC-MS analysis, previously and successfully used for characterization of anthraquinones, flavonoids and tannins from plant extracts and historical samples, has been tested on indigoid dyestuffs. An analytical procedure based on silylating agent N,O-bis-(trimethylsilyl)-trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS), was applied on pure molecules of indigotin and indirubin and on plant extracts of Indigofera tinctoria L. and Isatis tintoria L. Preliminary tests have been done to establish the chromatographic conditions and the derivatization amounts most suitable for the simultaneous detection of indigoid molecules and of the other natural compounds, such as fatty acids, carboxylic acids and sugars, contained within the plant extracts. In order to assess the capacity and the sensitivity of the analytical procedure in the typical archaeometric applications, wool samples dyed in laboratory with indigo were analysed mimicking the sample amounts typically available with historical objects. The EI spectra of main silylated derivatives of indigoid molecules obtained in this way constitute the necessary data set for the characterization of natural extracts and historical works of art. Subsequently the procedure has been applied on historical samples for the detection of indigo and of other dyestuffs eventually contained in samples. Additional information, useful for restoration and preservation of works of art, could be also obtained on the nature of stains and smudges present on the sampled textile material. The GC-MS method turns out to be an efficient and fast analytical tool also for the identification of natural indigo in plants and textiles artefacts, providing results complementary to those coming from HPLC.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
