Forensic dye analysis in cultural heritage: Unraveling the authenticity of the earliest Persian knotted-pile silk carpet.

The use of forensic dye analysis in the field of cultural heritage is introduced, and a case study is presented determining the dating of a potentially important textile fragment from the Cleveland Museum of Art. The fragment, attributed on stylistic grounds to the 15th century, is purportedly the oldest surviving example of a Persian knotted-pile silk carpet. Raman spectroscopy combined with liquid chromatography - mass spectrometry determined the dyes used in the fragment include Metanil yellow, Congo red, and indigo, possibly in its synthetic form. Based on the dates of introduction for these dyes (1879, 1884, and 1897, respectively) and the first appearance of the textile fragment in 1928, the object is shown to be almost certainly a late 19th or early 20th century creation. Furthermore, impurities found in the red dye are suggested as potential markers of a pre-1970s synthetic route for manufacturing Congo red or possibly degraded Congo red due to environmental pollutants.

Development of polymer-membrane based electrodes for suramin.

The development of a polymer membrane-based electrode to measure the anionic drug suramin in buffered saline and biological samples is described. A large non-equilibrium, steady state EMF response is observed toward suramin, and judicious choice of the polymer membrane components allows for adjustment of the dynamic range of the electrode. The optimized membrane for use in the toxic suramin range consists of 25 wt% tridodecylmethyl ammonium chloride, 55 wt% bis-2-ethylhexyl sebacate, and 20 wt% Pellethane. Although this electrode can be used to directly quantify suramin in human plasma, determination of suramin that is not affected by the background concentration of small anions is best achieved by simple potentiometric titrations with polycationic protamine monitored with a protamine-sensitive electrode.

Polyion-sensitive membrane-based electrodes for heparin-binding foldamer analysis.

Polymer membrane-based electrodes sensitive to low molecular weight heparin (LMWH) have been used to examine the binding between several preparations of LMWH and heparin-binding foldamers, which have recently been developed as potential inhibitors of the anticoagulant activity of LMWHs. It was found that the structure of the heparin-binding foldamer affects the equilibrium binding constant, K(eq), determined by analysis of the titration curves of the foldamers with LMWHs monitored with these electrodes, and further, the strength of binding depends on the specific LMWH preparation. Additionally, polymer membrane-based electrodes utilizing dinonylnaphthalene sulfonate as the ion-exchanger were developed to measure the heparin-binding foldamers directly in whole blood, and the response was found to depend on the lipophilicity and charge density of the foldamer.