DIN ISO 22036:2009-06

Inductively coupled plasma-atomic emission spectrometry (ICP-AES) may be used to determine trace elements in solution. The solution is dispersed by a suitable nebuliser and the resulting aerosol is transported into the plasma torch. In a radio-frequency inductively coupled plasma the solvent is evaporated, the dried salts are then, vaporised, dissociated, atomised and ionised. The atoms or ions are excited thermally and the number of photons emitted during transition to a lower energy level are measured with optical emission spectrometry. The spectra are dispersed by a grating spectrometer, and the intensities of the emission lines are monitored by photosensitive devices. The identification of the element takes place by means of the wavelength of the radiation (energy of photons), while the concentration of the element is proportional to the intensity of the radiation (number of photons). The ICP-AES method can be used to perform multi-element determinations using sequential or simultaneous optical systems and axial or radial viewing of the plasma. Table 1 shows examples for recommended wavelengths, and detection limits for one instrument. Using other instruments may lead to different detection limits. Adoption of other wavelengths is possible.