spectroscopy (AES), more commonly referred to as emission spectroscopy, is a
spectroscopic technique which examines the wavelengths of photons emitted by
atoms or molecules during their transition from an excited state to a lower
energy state. Each element emits a characteristic set of discrete wavelengths
according to its electronic structure; by observing these wavelengths the
elemental composition of the sample can be determined. AES detectors operate by
passing a continuous stream of target vapor to a burner where it is combusted
by a hydrogen flame, resulting in excited state ions. The photoemission from
the flame is passed to a diffraction grating and the resulting emission
spectrum is then detected by a photo detector array. In this way, spectral
lines for all elements in a sample may be recorded simultaneously. AES is most useful for
samples that are dissolved or suspended in aqueous or organic solutions. AES is
typically employed as a bench top instrument.
It is a mature technology available from a number of manufacturers.