Construction of LIBS calibration curves and determination of limits of detection (LOD) in single and double pulse configuration for quantitative LIBS analysis of ancient bronze coins

The LIBS technique has been utilized for a long time in the Cultural Heritage field. Moreover, the potential of this technique for accurate quantitative analysis could be greatly improved using an innovative experimental setup based on the use of two laser pulses suitably retarded. On the basis of the analyses performed on a set of certified bronze samples, reference curves were built and Limits of Detection (LOD) were calculated in order to obtain quantitative information about the composition of three ancient bronze coins. The coins are Punic, of a kind struck in many Punic mints of the Mediterranean basin such as Carthage and in Sicilian cities, as well as in Sardinia, in III cent BC. The detection limits for the elements of interest were calculated under the optimum conditions for the doublepulse configuration and compared with those obtained under the optimum conditions for single-pulse configuration. Significantly improved detection limits were achieved, for all the elements investigated.