Micro-domain analysis of skin samples of moor-mummified corpses by evanescent wave infrared spectroscopy using silver halide fibers

Infrared microscopy plays an important role in chemical micro-domain analys is of inhomogeneous materials. A simple experimental arrangement based on f iber-optics, employing bent silver halide fibers of sub-millimeter diameter cross-section, was used for infrared ATR-measurements with a minimum spot size of 20 x 60 mum(2). It was applied for the analysis of skin specimens a nd hair samples of mummified corpses, preserved under bog conditions. The d esiccated dermis samples looked leather-like, but were rather brittle, so t hat micro-ATR measurements by a fiber probe were appropriate. Comparable AT R-results were obtained using an IR-microscope. Composition along perpendic ular dermis cross-sections was evaluated by comparison with spectra from re ference materials. Natural dermis samples are mainly composed of collagen, primarily of type I and III, which was still found in the mummies' skin. Th e surfaces of the skin samples displayed chemical changes from moor constit uents, while the center of the dermis cross-section consisted of unmodified collagen. Keratin in hair samples was also well preserved apart from surfa ce changes. which had been caused by the bog chemistry in these samples and are clearly manifested in the infrared spectra. (C) 2001 Elsevier Science B.V. All rights reserved.