Illumination atomic spectroscopy

Atomic Absorption Spectroscopy. One of the more sensitive instruments used to detect metal-containing toxicants is the AA spectrophotometer. Samples are vaporized either by aspiration into an acetylene flame or by carbon rod atomization in a graphite cup or tube (flameless AA). The atomic vapor formed contains free atoms of an element in their ground state, and when illuminated by a light source that radiates light of a... 

Since the molecular composition of materials is not apparent to the naked eye, more sophisticated, indirect techniques are required to determine the structure of a material at a microscopic level. Spectroscopy, in a manner analogous to human vision, uses a beam of particles to illuminate a sample of the material. A machine eye then sees the scattered or transmitted particles and uses the characteristics of these particles to determine the chemical structure and composition of the sample. The particular type of spectroscopy that a chemist might use depends, in part, on the atomic or molecular characteristics that are assumed to be relevant to the sample. 

The use of so-called astronomical spectroscopy yields data related to the composition of celestial objects. Since different materials have different emission spectra, a comparison of the light (or other particles) emitted from stars, nebulae or galaxies, for example, with the light emitted from known materials provides a basis for determining the atomic or chemical make-up of these objects. In this case, no illuminating beam is required this form of spectroscopy is, in this sense, passive. 

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