Comparative study of different LA ICP MS equipment in studying Pb isotope ratios to assess the origin of archaeological artifacts.

Predominantly natural or anthropic processes, what occurs on the earth surface is due to the presence of associations of physical/chemical elements characteristic of the generating process and geographically associated with its area of ​​occurrence. The geochemical signal identified, for example, in waters and sediments is a sum of contributions originating from the natural environment. The origin of a material or history is always fundamental in archaeological research.

Therefore, analyzing elements of samples back to their origin by the composition of objects through sophisticated techniques of physical chemical analysis, including the process of elucidating issues such as the age and origin of the material, manufacture, and identification of its components.

This work applies the methodology usually used for geochronology, the detection of Pb stable isotopes, as the first tool for the determination the isotope ratios in three coins of Roman Empire. Then, a comparative study between the results delivered by two different equipment was made, in order to evaluate the best equipment and methodology. The equipment were Neptune Thermo^TM , multicollector and Elements Thermo^TM single collector. In both cases the samples were introduced in the ICP MS by laser ablation (LA).

Results showed some advantages by using Elements Thermo^TM firstly due stronger statistics and also because that equipment is less sensitive to sample contaminations.