Characterization of jewellery products by laser-induced breakdown spectroscopy

The suitability of laser-induced breakdown spectroscopy (LIBS) for the characterization of jewellery products is demonstrated by the development of a method based on the use of an Nd-YAG laser (operating at 532 nm) which induces ablation of the material and the production of a plasma whose emission reaches 1/8 m spectrograph (connected to a coupled charge detector (CCD)) through an optic fiber. The treatment of the instrumental signal provides enough analytical information, both for identifying and quantifying the major metals present in this type of material, The method proposed has been developed both by multivariate optimization and calibration procedures with application of the appropriate quality criteria. The chemometric analysis of the data and the use of PLS regression for calibration guarantee the ruggedness of the proposed method. The study of the emission spectra allows characterization of the most common noble metals (gold and silver) as well as other metals present in jewellery pieces. (C) 2002 Elsevier Science B.V. All rights reserved.