Comparison of NIR spectroscopy coupled to chemometrics and derivative thermogravimetry for relative dating of human fossil bones

The possibility of using near-infrared spectroscopy (NIR) coupled to chemometric exploratory data processing in order to obtain a fast, cheap and nondestructive dating of human fossil bones is presented and discussed. The proposed approach has been applied to the differentiation of human fossil bones from two necropolises in the Middle Nile (Saggai and Geili). Principal component analysis of the spectral data after suitable pretreatment (standard normal variate + first derivative) allowed to evidence cluster of bones corresponding to the different antiquity of the samples, thus indicating that the proposed approach can lead to an accurate (although relative) dating of the fossil samples. Analysis of the PCA loading suggested that the spectral region that are most relevant for the observed differentiation is 4000–4500, 5150–5801 and 6898–7411 cm−1. A confirmation of the reliability of what found using NIR spectroscopy was obtained by comparing the results to those outcoming from the DTG analysis onto the same bone samples followed by PCA, according to a thermogravimetric–chemometric approach already successfully applied in previous researches. Lastly, in order to obtain a more holistic characterization of the samples, a further PCA processing was carried out after “fusion” of data from both analytical techniques. © 2017 Akadémiai Kiadó, Budapest, Hungary