Strontium in barium sulphate as a discriminating factor in the forensic analysis of tool paint by SEM/EDS

•X-mapping has made it possible to discriminate between red tools that otherwise would not have been distinguished.•A detailed examination of the concentration of strontium in barium sulphate allowed this discrimination to be made.•Underused in the forensic field, X-ray mapping allows better characterisation of tool paints. In the context of forensic tool paint analysis, the development of analytical strategies to distinguish between different tools is of great interest in order to form a better opinion on whether or not a trace of paint seized at a crime scene originates from a tool found, for example, during a search of a house. A study was therefore conducted on the potential of using X-ray mapping to discriminate red tools that are not otherwise distinguished by standard analytical techniques (i.e. optical microscopy, infra-red spectroscopy, Raman spectroscopy). In this study, the presence of trace amounts of strontium – revealed by X-ray mapping – in the main mineral filler, namely barium sulphate, allowed the discrimination of different tools using a statistical approach. This study is one example among others of the potential of X-ray mapping for a better characterisation of tool paints in a forensic context.