AIC's 42nd Annual Meeting

The analysis of an organic dyestuff on an historic textile is met with the challenges of chromophore detection at very low concentration in a minute sample from an object of cultural significance susceptible to degradation. Historically, organic dye analysis has been achievable by methods including: high performance liquid chromatography (HPLC) often coupled to additional analytical tools, surface-enhanced Raman spectroscopy (SERS), and various mass spectrometric methods. The drawbacks of these methods are their requirements for either time intensive dye extraction procedures or nanoparticle preparation protocols. This presentation introduces DART-TOF (direct analysis in real time – time-of-flight) mass spectrometry as a novel method for organic chromophore analysis in natural fibers.  High resolution time of flight mass spec with direct analysis in real time ionization is very rapid, possessing the requisite sensitivity to identify organic colorants in less than 1 minute. Furthermore, analysis by DART mass spec typically requires no extraction of the dye prior to analysis, and is accomplished with fiber samples less than 0.5 cm in length, weighing no more than 1 mg.  In our initial exploration of the technique, we conducted analyses of dyestuffs as powder, in solution, and in botanical source materials.  Further development involved the creation of dyed fiber reference materials. To date, more than 40 dye colorants have been identified by DART-TOF mass spec, representing the following classes of dyes:  quinones (anthraquinones and naphthoquinones), flavonoids, indigoids, carotenoids, tannins, and curcuminoids.  We have successfully identified organic dyes in situ in fibers from historic textiles including rugs, tapestries, and Huari garments.  Recently, DART-TOF was used to confirm the anecdotal account regarding the dyeing history of the Civil War era Sam Davis coat in the collection of the Tennessee State Museum.  These findings demonstrate that DART-TOF mass spectrometry has potential as an additional tool in the challenging analysis of organic dyes and possesses the requisite sensitivity and the advantage of simplicity without the preparatory requirements of other techniques.