Thin-layer chromatography/metal underlayer-ATR FTIR methodology for the study of synthetic dyes extracted from degraded wool fibres

This paper proposes an analytical protocol for the identification of synthetic dyes in degraded wool fibres using a multi-step micro-extraction protocol coupled with Thin Layer Chromatography (TLC)/Metal-Underlayer Attenuated Total Reflection (MU-ATR) FTIR. TLC/MU-ATR is a new enhanced FTIR method, which enables even very few nanograms of analyte to be detected. The efficacy of the method was tested on synthetic dyes (both acid and base), which were artificially aged at 20 h, 60 h, 140 h and 305 h using UV light (∼365 nm). The method was validated on real samples from a pattern book dated 1893. Coupling chromatographic separation with enhanced spectroscopic detection, the method allows substantial reduction of matrix interference by means of TLC and can identify the dyes even in degraded states.