Atomic absorption spectroscopy (AAS)
Atomic absorption is a stimulated absorption transition process. When a radiation passes through a free-atom vapor and the incident radiation has a frequency equal to the frequency of the energy required for the outer electrons in the atom to transition from the ground state to the higher energy state, the atoms resonate. Atomic absorption spectroscopy is based on the material generated by atomic vapor absorption of light of a specific wavelength for quantitative analysis. Atomic absorption light wavelengths are usually in the UV and visible region (190 ~ 900nm).
Atomic absorption spectrometry is mainly used for the analysis of trace and trace components in a sample. It analyzes most of the elements in the periodic table (but the detection limits of the elements are different depending on the nature of the element itself). The method has many advantages such as good selectivity, high precision, wide range of application, accuracy and convenience.
Atomizer is one of the key components of atomic absorption spectrometer (AAS), its function is to provide energy to dry, evaporate and atomize the sample. To achieve the atomization method, there are two most commonly used: flame method and graphite furnace electric method. According to these two methods, commonly used atomic absorption spectrometer: flame atomic absorption spectrometer, graphite furnace atomic absorption spectrometer and flame - graphite furnace atomic absorption spectrometer. The Flame Atomic Absorption Spectrometer is simple in structure and capable of analyzing most of the metal elements. Although graphite furnace atomic absorption spectrometer is relatively complicated in structure, it can analyze some elements that can not be analyzed by the flame method. The two kinds of instruments have different advantages and complement each other.
Flame atomic absorption is most commonly used for the air - acetylene flame, the flame temperature of about 2300 degrees, for high temperature elements such as Al, Si, Sn and other elements of the test will need to use the temperature can reach 2900 degrees of nitrous oxide - acetylene flame. Flame atomic absorption detection is usually sub-ppm level above. Graphite furnace atomic absorption of high and low temperature elements can be detected, the detection capacity is usually sub-ppb level or ppb level, but for some elements such as La-based elements, its detection is poor. At the same time, most of the non-metallic elements such as As, Se, Hg, Pb, and hydride generation technology or flow injection technology can improve the detection limit.
Atomic absorption spectrometry is mainly used for the analysis of trace and trace components in a sample. It analyzes most of the elements in the periodic table (but the detection limits of the elements are different depending on the nature of the element itself). The method has many advantages such as good selectivity, high precision, wide range of application, accuracy and convenience.
Atomizer is one of the key components of atomic absorption spectrometer (AAS), its function is to provide energy to dry, evaporate and atomize the sample. To achieve the atomization method, there are two most commonly used: flame method and graphite furnace electric method. According to these two methods, commonly used atomic absorption spectrometer: flame atomic absorption spectrometer, graphite furnace atomic absorption spectrometer and flame - graphite furnace atomic absorption spectrometer. The Flame Atomic Absorption Spectrometer is simple in structure and capable of analyzing most of the metal elements. Although graphite furnace atomic absorption spectrometer is relatively complicated in structure, it can analyze some elements that can not be analyzed by the flame method. The two kinds of instruments have different advantages and complement each other.
Flame atomic absorption is most commonly used for the air - acetylene flame, the flame temperature of about 2300 degrees, for high temperature elements such as Al, Si, Sn and other elements of the test will need to use the temperature can reach 2900 degrees of nitrous oxide - acetylene flame. Flame atomic absorption detection is usually sub-ppm level above. Graphite furnace atomic absorption of high and low temperature elements can be detected, the detection capacity is usually sub-ppb level or ppb level, but for some elements such as La-based elements, its detection is poor. At the same time, most of the non-metallic elements such as As, Se, Hg, Pb, and hydride generation technology or flow injection technology can improve the detection limit.
