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Energy-dispersive X-ray spectrometry (EDX) is one of the most applied methods used for the analysis of the chemical composition of solids and thin films. Recent progress in EDS (Energy Dispersive X-ray Spectrometer) technology has increased the general performance also in the energy range < 1 keV addressing low Z elements. Suitable test materials to be employed especially to check the low-energy EDS performance – also in line with ISO 15632 - are rather limited and mainly based on C K and F K lines. In order to obtain valid results in laboratories accredited in compliance with ISO/IEC 17025 it is necessary to periodically check the instrument performance.
Advances in scanning electron microscopy (SEM) enable the high-resolution imaging of single nanoparticles (NPs) with sizes well below 10 nm. The SEM analysis in transmission mode (T-SEM) of NPs on thin film supports has many benefits when compared to the analysis of NPs on bulk substrates. The enhanced material (mass - thickness) contrast of the T-SEM imaging mode is well suited for in-depth and, particularly valuable, to very accurate, traceable, lateral dimensional measurements of NPs. Compared to samples prepared on bulk substrates, T-SEM with energy dispersive X-ray spectroscopy (EDS) achieves a drastically improved spatial resolution of the emitted X-rays. The poor signal-to-noise ratio of the X-ray spectra emitted by a single nanoparticle (NP) can be improved by the use of high-sensitivity (high collection solid angle) silicon drift (SDD), energy-dispersive X-ray spectrometers (EDS). The EDS spectral imaging of a single NP with a spatial resolution below 10 nm has become possible. This is demonstrated by means of various examples of nanostructures. Advanced data processing of T-SEM/EDS results sets the stage for the automated classification of NPs by feature analysis. This method combines the detection of morphological structures of interest by image processing of T-SEM micrographs with the chemical classification by EDS.