Use of LA-ICP-MS technique with SEM-EDS analysis in the study of finishing layers

The investigation of the finishing layers in artworks is of major concern, as important information on the artistic technique can be suggested. The study is usually carried out with Scanning Electron Microscopy equipped with Energy Dispersive Spectroscopy (SEM-EDS), but in those cases where very similar compositions are detected, more sensitive techniques are called for. Laser Ablation-Mass Spectrometry equipped with Plasma source (LA-ICP-MS) allows very sensitive element analysis of solid surfaces sampled by means of a laser. It is an emerging methodology, applied only in a few cases in the field of cultural heritage. The integration of the two techniques has been studied and applied on the finishing layers of Baroque stucco decorations, in order to define the artistic technique in terms of raw materials, stratigraphy and working tools.