Chemie und Prozesstechnik
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Reclaimed asphalt pavements (RAP) with increased contents of polycyclic aromatic hydrocarbons (PAH) are restricted for reuse due to their harmful effects on humans and the environment. This work investigated whether Fourier transform infrared (FTIR) spectroscopy is suitable for a fast and simple identification and quantification of PAH in binders recovered from reclaimed asphalts. For this, the binders from 34 RAP samples were recovered using a rapid procedure developed at the Universität Kassel and were examined with infrared spectroscopy. The obtained spectra were pre-processed (Standard Normal Variate transformation, 1st derivative) and evaluated using a combination of factor analysis and linear discriminant analysis. The results showed that various PAH groups with differently pronounced aromatic structures are present in the binders.
However, with FTIR spectroscopy combined with the multivariate methods, a statistical model was developed allowing for the differentiation between the PAH groups and also for the distinction between PAH contents below or above the threshold of 25 mg/kg valid in Germany.
This talk will be divided into two parts. In the first part I will present the analytical techniques and the equipment used by the Centre for the Study of Manuscript Cultures that can be applied for the study of decorated papers. The analyses aim to determine the constituent materials of papers, pigments, dyes and metals and the techniques used for their production. I will focus in particular on the kind of information these techniques allow us to gather: through optical microscopy we conduct fibre analysis in order to identify the plant used as raw material in paper production while Reflectography, X-Ray Fluorescence and InfraRed, Raman and Visible Reflectance Spectroscopy are used to study the sizing agents, the pigments, dyes and metals. In the second part I will show some results obtained by the application of these techniques on a few Persianate manuscripts, dating between the 15th and 17th centuries, belonging to the corpus of Ilse Sturkenboom.
The aim of this study was to identify specific chemical bonds and characteristic structures in melanoidins formed from D-glucose and L-alanine between 130 and 200 °C. The results might be used to control the type and amount of melanoidin produced during food processing. For this purpose, complementary techniques, such as FTIR, NMR, EPR, and MALDI-ToF, were employed. At 160 °C color, solubility and UV/Vis absorption change characteristically and consequently, structural transformations could be observed in FTIR and NMR spectra. For example, sharp signals of N-H, C-N, and C-H oscillations in the L-alanine spectrum are prone to inhomogeneous broadening in melanoidins prepared above 150 °C. These changes are caused due to formation of heterogeneous macromolecular structures and occur during condensation reactions that lead to an increasing loss of water from the melanoidins with increasing temperatures. Additionally, MALDI-ToF-MS indicates the polymerization of glyoxal/glyoxylic acid and EPR shows the formation of radical structures.