What Is Atomic Emission Spectroscopy?

Atomic Emission Spectrometry (AES) uses qualitative and quantitative analysis of elements to determine the composition of a substance by using the atomic or ion emission characteristic spectrum of each element under thermal or electrical excitation. Atomic emission spectrometry can analyze about 70 elements (metal elements and non-metal elements such as phosphorus, silicon, arsenic, carbon, boron, etc.). Under normal circumstances, it is used for the determination of components below 1%, the detection limit can reach ppm, the precision is about ± 10%, and the linear range is about 2 orders of magnitude. This method can be effectively used to measure high, medium and low content elements.

Atomic emission spectroscopy refers to an analysis method that uses the spectrum formed by the radiation emitted by excited atoms to compare with the standard spectrum to identify what kind of substance is contained in the substance. Using arcs, sparks, etc. as the excitation source, the gaseous atoms or ions emit ultraviolet and visible radiation after being excited. A certain element atom can only generate spectral lines of certain wavelengths. According to whether certain characteristic spectral lines appear in the spectrogram, it can be determined whether there is an element. According to the intensity of the characteristic spectral line, the content of a certain element can be determined. All the elements in the test substance can be shown on the map in one inspection, and then compared with the standard map. There are more than 70 types of measurable elements. Sensitivity, good selectivity and fast analysis speed. In judicial identification, it is mainly used for qualitative analysis of trace metal elements in soil, paint, dust and other substances. Quantitative analysis is more complicated and inaccurate ^[1]

Atomic emission spectroscopy is based on

Atomic emission spectroscopy (AES) is an analytical method that uses the characteristic spectrum of an atom or ion to be stimulated and emitted under certain conditions to study the chemical composition of a substance. According to different excitation mechanisms, there are three types of atomic emission spectra:

The emission spectrum of an atom's extranuclear optical electrons when excited by thermal energy and electric energy. The atomic emission spectroscopy is generally referred to as arc, electric spark and

In 1859,

Atomic emission spectrum line intensity

The atom transitions from an excited state i to a low energy level j, and the intensity of the emitted spectral line is proportional to the number of excited state atoms.

In thermodynamic equilibrium, the distribution between the number of ground-state atoms N0 and the number of excited-state atoms Ni per unit volume follows the Boltzmann distribution law:

gi and g0 are the statistical weights of the excited state and the ground state; Ei: is the excitation energy; k is the Boltzmann constant; T is the excitation temperature;

Emission line intensity:

Factors affecting the intensity of spectral lines:

The smaller the excitation energy, the stronger the spectral line intensity;

As the temperature increases, the intensity of the spectral line increases, but it is easy to ionize.

Atomic emission spectroscopy

Plasma: An overall electrically neutral aggregate containing particles such as molecules, ions, and electrons in a gaseous form. The distribution of temperature and atomic concentration in the plasma is not uniform. The intermediate temperature and excited atomic concentration are high, and the edges are reversed.

Self-absorption: The radiation emitted by the center is absorbed by the same kind of ground-state atoms at the edges, which reduces the intensity of the radiation.

Self-etching: When element concentration is low, no self-absorption occurs. As the concentration increases, the self-absorption becomes more serious. When a certain value is reached, the center of the spectral line is completely absorbed, as if two lines appear. This phenomenon is called self-erosion ^[1] .