Interference and elimination methods of atomic absorption spectrometer

The instrument radiates light with characteristic spectral lines of the elements to be measured from the light source, and is absorbed by the ground state atoms of the elements to be measured in the sample vapor when passing through the sample vapor. The content of the elements to be measured in the sample is determined by the degree of attenuation of the radiation characteristic spectral lines.

Application of atomic absorption spectrometer accessories

Atomic absorption spectrometer is widely used in metallurgy, geology and mining because of its sensitivity, accuracy and simplicity.

Atomic absorption refers to the absorption phenomenon of gaseous atoms to the characteristic spectral lines radiated by the same kind of atoms. When the radiation is projected onto the atomic vapor, if the energy corresponding to the radiation wavelength equals the energy needed for the protoatomic absorption spectrometer to transit from the ground state to the excited state, the absorption spectrum will be generated. The ground state atoms absorb energy, and the outermost electrons generate transitions, from low-energy states to excited states.

Composition of atomic absorption spectrometer

Atomic absorption spectrometer is composed of light source, atomization system, spectroscopic system and detection system. A light source as a source of light requires that the sharp spectrum of the elements to be emitted has sufficient intensity, small background and stability. Generally, hollow cathode lamp electrodeless discharge lamp B atomizer can be divided into premixed flame atomizer, graphite furnace atomizer, quartz atomizer. Quatzfurnace atomizer, cathode sputtering atomizer. A flame atomizer: It consists of sprayer, pre-mixing chamber and burner. It is a simple and reproducible B graphite furnace atomizer. It is a kind of system that atomizes the sample in graphite tube wall, graphite platform, carbon rod sample hole or graphite crucible by electric heating to high temperature. Tubular graphite furnace is the most commonly used atomizer. Atomization procedures are divided into drying, ashing, atomization, high-temperature purification atomization efficiency: at adjustable high temperature sample utilization rate of 100% high sensitivity: its detection limit of 10-6 ~ 10-14 sample consumption is small: suitable for the determination of refractory elements C. A method of atomization is also called cryogenic atomization. It is mainly used in conjunction with vapor generation (hydride generation, mercury vapor generation and volatile compounds generation). D. The cathode sputtering atomizer bombards the cathode surface with positive ions produced by glow discharge, and directly converts the measured elements into atomic vapor from the solid surface. The performance of a C-splitter (monochromator) consisting of a concave mirror, a slit, or a dispersion element, a prism or a diffraction grating monochromator, means that the dispersion, resolution, and collecting power of the D-detection system are composed of a detector (photomultiplier tube), an amplifier, a logarithmic converter, and a computer.

Interference and elimination methods of atomic absorption spectrometer

Interference can be divided into: chemical interference, physical interference, ionization interference, spectral interference, background interference chemical interference elimination methods: changing the flame temperature, adding releasing agent, adding protective complexing agent, adding buffer background interference elimination methods: dual-wavelength method, deuterium lamp correction method, self-absorption method, Zeeman effect atomic absorption method Advantages and disadvantages of spectroscopic methods. (1) the detection limit is low and the sensitivity is high. The detection limit of flame atomic absorption spectrometry can reach 10-9 grade and graphite furnace atomic absorption spectrometry can reach 10-14-10-10 G. (2) the accuracy of analysis is good. The relative standard deviation of the flame atomic absorption spectrometry is less than 1%, which is close to the classical chemical method. The accuracy of graphite furnace atomic absorption spectrometry is generally 3% to 5%. (3) the analysis speed is fast. Atomic absorption spectrometer can continuously measure 6 elements in 50 samples in 35min. (4) a wide range of applications. More than 70 elements can be determined, not only metallic elements can be determined, but also non-metallic elements and organic compounds can be determined by indirect atomic absorption spectrometry. (5) the instrument is relatively simple and easy to operate. (6) The disadvantage of AAS is that the simultaneous determination of many elements is still difficult, and the sensitivity of some elements is not satisfactory.

Atomic absorption spectrometer accessories