Exploratory analysis of micrographic Teflon images

Some analytical techniques are able to produce images, making if possible t o obtain a large amount of information. Working with images, the pixels can be treated like objects in a data matrix. In this way, a multi-way PCA of micrograph images was applied to the internal surface of a Teflon coil used for microwave sample digestion. This Teflon coil was used for 120h and had been attacked with different acids. It was cut into 3 pieces (namely: init ial, medium and central portions) in order to obtain 7 micrographs (2 for i nitial, 2 for medium and 3 for the central part). A micrograph of a piece f rom a new Teflon coil was used for comparison. With these 8 micrographs, it was possible to establish a three-dimensional arrangement. After multi-way PCA was applied to the Teflon surface images, was possible to group a grea t amount of information and to characterise different parts of this coil.