The typical energy resolution
for EDS is of on the order of 150 eV. This is suffcient in most cases
for resolving peaks of different elements, but is inadequate for detecting chemical shifts of the atoms which are of the order of a few electronvolts. EDS
is thus mainly used for composition analysis.
For low-energy EDS measurements of heavy elements in bulk materials, the spatial resolution can be enhanced if the X-ray lines of a proper low-excitation energy are used. With an accelerating voltage of 5 kV, the K line is available only for atomic numbers below 20, above which L lines is needed, and M lines must be used for atomic numbers above 42. This application of low energy X-ray lines sacrifice the efficiency of X-ray generation and is subject to chemical bonding effects.