As with any spectral analysis method, a group of spectral lines comprises a fingerprint of the unknown element. If more than one element is present, as is generally the case, spectral overlap may occur and the analyst must use care to avoid error. In

addition, certain interfering lines will always be present (see Table 8.1) and must be considered. If K spectral lines are excited, the analyst should look for both the Ka and the KfJ to verify the identity. If overlap has masked one or both of these lines, it may be possible to use higher order lines from the same series ('Iible 8.2) or lines from a different series to obtain a positive identification. L spectra can also be used to identify elements with atomic numbers greater than 40. In this instance, the analyst initially looks for the La line, then uses other lines including LfJ and Ly lines to verify the choice.