Method and materials of detection device component in one room

The invention relates to a method and materials detecting apparatus constituting a part (10), in which is measured the chemical elements forming a surface of the workpiece. According to the invention, effectively detect the presence of a surface layer on the workpiece, and, if desired, initiate the workpiece surface to effect again the detection depth beyond the surface layer. The invention further provides a device particularly suitable for this implementation which in particular on the sorting black polymers, with identification of material and flame retardant detection.