Managing complex Synchrotron radiation FTIR micro-spectra from historic bowed musical instruments by chemometrics

The intrinsic complexity of the coating systems on historical bowed string musical instruments complicates the characterization of the different materials that have been subsequently spread on the wood. Even more challenging is the identification of their spatial distribution in the sequence of the finishing layers. To face both issues, in this study we combined Synchrotron radiation micro - FTIR in reflection geometry and Chemometrics for the investigation of five micro-samples mounted in crosssections, removed from musical instruments made by Antonio Stradivari, Francesco Ruggeri and Lorenzo Storioni. A classification model based on Partial Least Squares – Discriminant Analysis aimed at discriminating the organic materials through infrared signals was developed. High model specificity (> 0.9) was reached in prediction, doing the groundwork for the application of a fast and rigorous methodological approach.