Rapid Identification for the Pterocarpus Bracelet by Three-Step Infrared Spectrum Method.

In order to explore a rapid identification method for the anti-counterfeit of commercial high value collections, a three-step infrared spectrum method was used for the pterocarpus collection identification to confirm whether a commercial pterocarpus bracelet (PB) was made from the precious species of Pterocarpus santalinus (P. santalinus) . In the first step, undertaken by Fourier transform infrared spectroscopy (FTIR) spectrum, the absorption peaks intensity of PB was slightly higher than that of P. santalinus only at 1594 cm -1 , 1205 cm -1 , 1155 cm -1 and 836 cm -1 . In the next step of second derivative IR spectra (SDIR), the FTIR features of the tested samples were further amplified, and the peaks at 1600 cm -1 , 1171 cm -1 and 1152 cm -1 become clearly defined in PB. Finally, by means of two-dimensional correlation infrared (2DIR) spectrum, it revealed that the response of holocellulose to thermal perturbation was stronger in P. santalinus than that in PB mainly at 977 cm -1 , 1008 cm -1 , 1100 cm -1 , 1057 cm -1 , 1190 cm -1 and 1214 cm -1 , while the aromatic functional groups of PB were much more sensitive to the thermal perturbation than those of P. santalinus mainly at 1456 cm -1 , 1467 cm -1 , 1518 cm -1 , 1558 cm -1 , 1576 cm -1 and 1605 cm -1 . In addition, fluorescence microscopy was used to verify the effectiveness of the above method for wood identification and the results showed good consistency. This study demonstrated that the three-step IR method could provide a rapid and effective way for the anti-counterfeit of pterocarpus collections.