How are atomic emission spectra used in analysis?

Atomic emission spectra are used in analysis to identify elements and determine their concentration in a sample.

Atomic emission spectra are a fundamental tool in analytical chemistry, particularly in spectroscopy. They are unique to each element, much like a fingerprint, and can be used to identify unknown elements in a sample. This is based on the principle that when atoms are excited, they emit light of specific wavelengths, which correspond to different colours. These wavelengths form a spectrum, and the pattern of wavelengths is specific to each element.

The process begins by introducing a sample into a flame, plasma or other source of high energy. This energy excites the atoms, causing them to emit light. This light is then passed through a prism or diffraction grating to separate it into its component wavelengths, creating a spectrum. The spectrum is then analysed to identify the wavelengths present, and thus the elements that produced them.

In addition to identifying elements, atomic emission spectra can also be used to determine the concentration of an element in a sample. This is done by comparing the intensity of the emitted light to a standard curve. The intensity of the light is proportional to the number of atoms emitting it, so a higher intensity indicates a higher concentration of the element.

Furthermore, atomic emission spectra can be used to study the structure of atoms and molecules. By analysing the spectrum, chemists can determine the energy levels of the electrons in an atom or molecule. This information can be used to understand the chemical properties of the substance, such as its reactivity or bonding behaviour.

In conclusion, atomic emission spectra are a powerful tool in analytical chemistry. They allow chemists to identify elements, determine their concentration, and study their structure. This makes them invaluable in a wide range of applications, from environmental monitoring to forensic science.