Atomic Absorption Spectroscopy (AA)

Posted March 03, 2018

The term "spectroscopy" means the observation and study of the spectrum, or record of a species such as a molecule, an ion or an atom, when these species are excited by an appropriate energy source One of the pioneers in spectroscopy was Isaac Newton, who in the early 1600s observed and studied the behavior of sunlight as it passes through a prism.

In 1831, JF Herschel demonstrated that the salts of different metals produce different colorations to the flame when the salts dissolved or in direct form are put in contact with this one. For example calcium salts give the flame an orange color, sodium a yellow color, potassium a violet, copper a blue-green, strontium a yellow-green, and so on. These observations were later corroborated by other researchers suggesting that in this way the salt forming metal could be identified in a specific chemical compound. Kirschoff and Bunsen in 1859 extended the knowledge of the nature of this phenomenon, when the colorful light produced by the metal in the flame caused it to fall into an optical deposit separating the radiation emitted by the metal, the sunlight. It is observed that each metal that emits radiation of different color, has lines that appear in different positions in the screen or field of observation, and in this instrument that was called spectroscope (spectroscope = observation of the spectrum).

this is independent of the conditions under which the experiment is performed as well as the nature of the metal salt and depends only on the metal. Additionally, the line strength is directly related to the concentration of the element in solution.

At the beginning of the twentieth century, all the elements of the periodic table were not known, and errors were frequently made when new elements were discovered when they were already known elements.

the spectroscopy when the news came of having found some new element, was observed its spectrum. If this already coincided with the elements already known, the novelty of the element was discarded, if on the contrary it did not coincide with any of the spectra of elements already known the test was unobjectionable and it was considered one more of the list of chemical elements. Although the applications of the spectroscopy in the qualitative analysis were almost immediate, its usefulness in the quantitative aspect had to wait many years, since the scientific and technological development of that moment was insufficient.

Although as mentioned earlier, the potential of spectroscopy in quantitative analysis was known since the end of the last century, its development and wide application in the chemical analysis is so recent that in 1952,

The first commercial atomic absorption spectroscopy equipment for the quantification of metals.

This slowness in the adaptation of spectroscopic techniques to quantitative chemical analysis ivo has been offset by the high degree of development it has achieved in recent years.