What is the working principle of atomic absorption spectrometer?

According to the working principle of modern spectrometer, spectrometer can be divided into two categories: classic spectrometer and new spectrometer.

Spectrometer. Classical spectrometer is an instrument based on the principle of spatial dispersion. The new spectroscopic instrument is based on

Modulation principle instrument. The classic spectrometer is a slit spectrometer. The modulation spectrometer is a non-spatial spectrometer.

Yes, it uses a round hole to enter light. According to the principle of dispersion module, spectrometer can be divided into prism spectrometer,

Diffraction grating spectrometer and interference spectrometer.

OMA (Optical Multichannel Analyzer) is an optical multichannel analyzer developed in recent ten years.

A novel spectrum analyzer controlled by a photon detector (CCD) and a computer,

Integrated storage function. Because OMA no longer uses photosensitive latex, darkroom processing is avoided and omitted.

After a series of tedious processing and measurement work, the traditional spectral technology has undergone fundamental changes, greatly

The working conditions are improved and the working efficiency is improved; Using OMA for spectrum analysis, the basin measurement is accurate, fast and convenient.

And has high sensitivity, fast response time and high spectral resolution, and the measurement result can be immediately read out from the display screen or displayed by the display.

At present, it has been widely used in almost all spectral measurement, analysis and research.

In research work, it is especially suitable for detecting weak signals and transient signals.

4.2 Selection of Dispersion Elements and Determination of Optical Parameters of Spectrometer

4.2. 1 Selection of Dispersion Elements of Spectrum Analyzer

In the design of imaging spectrometer, the selection of dispersive elements is a key issue, which requires a comprehensive balance between prism and optical shed.

Advantages and disadvantages of dispersive elements [140-al]

The direct reading spectrum analyzer is a "Chinese" spectrum analyzer, and its operation is simpler and clearer.

Development history of atomic absorption spectrometry

Discovery and scientific explanation of atomic absorption phenomenon in the first stage

As early as 1802, when W.H.Wollaston was studying the continuous spectrum of the sun, he discovered the dark lines in the continuous spectrum of the sun. 18 17, J.Fraunhofer discovered these dark lines again when he was studying the continuous spectrum of the sun. Because the reasons for these dark lines were not known at that time, they were called Fraunhofer lines. 1859, when G.Kirchhoff and R.Bunson studied the flame spectra of alkali metals and alkaline earth metals, they found that the light emitted by sodium vapor would be absorbed when it passed through sodium vapor at low temperature. According to the fact that sodium emission line and dark line are in the same position in the spectrum, it is concluded that the dark line in the continuous spectrum of the sun is in the atmosphere around the sun.

Generation of the second stage atomic absorption spectrometer

As a practical analytical method, atomic absorption spectrometry started from 1955. This year, Australian Wals published his famous paper "Application of Atomic Absorption Spectrometry in Chemical Analysis", which laid the foundation for atomic absorption spectrometry. In the late 1950s and early 1960s, Hilger, Varian Techtron and Perkin-Elmer successively introduced commercial instruments for atomic absorption spectrometry, which developed the design idea of Valsi. In the mid-1960s, atomic absorption spectrometry began to enter a period of rapid development. See resources [1].

Generation of electrothermal atomic absorption spectrometer in the third stage

1959, Lviv of the Soviet Union published the first paper on electrothermal atomization technology. The absolute sensitivity of electrothermal atomic absorption spectrometry can reach10-12-10-14g, which makes atomic absorption spectrometry a step forward. In recent years, with the development of Zeeman effect and self-priming effect subtraction background technology, atomic absorption spectrometry can be successfully realized in high background. On this basis, the matrix improvement technology, platform and probe technology and the application of stable temperature platform graphite furnace technology (STPF) developed can effectively realize the atomic absorption determination of many complex samples. See reference [2]

Development of Atomic Absorption Analytical Instruments in the Fourth Stage

With the development of atomic absorption technology, the continuous updating and development of atomic absorption instruments have been promoted, while other scientific and technological progress has also provided technical and material basis for the continuous updating and development of atomic absorption instruments. In recent years, a microcomputer-controlled atomic absorption spectrophotometer has been designed by using continuous light source, step grating, light pipe and diode array multi-element analysis detector, which opens up a new prospect for simultaneous determination of multi-elements. The microcomputer-controlled atomic absorption spectrometry system simplifies the instrument structure, improves the automation degree of the instrument, improves the determination accuracy, and greatly changes the face of atomic absorption spectrometry. Coupled technologies (chromatography-atomic absorption spectrometry, flow injection-atomic absorption spectrometry) have attracted more and more attention. Chromatography-atomic absorption spectrometry (GC-AAS) not only solves the chemical speciation analysis of elements, but also can determine complex organic mixtures, which is a promising development direction.

Advantages and disadvantages of atomic absorption spectrometry

& lt 1 & gt； Low detection limit and high sensitivity. The detection limit of flame atomic absorption spectrometry can reach ppb level, while graphite furnace atomic absorption spectrometry

The detection limit of this method can reach10-10-10-14g.

The accuracy of<2> analysis is good. The relative standard deviation of high content elements in flame atomic absorption spectrometry can be as follows

The accuracy is close to the classical chemical method. The analytical accuracy of graphite furnace atomic absorption spectrometry is generally about 3-5%.

& lt3> analysis speed is fast. Atomic absorption spectrometer can continuously determine 6 elements in 50 samples within 35 minutes.

& lt4> has a wide range of applications. More than 70 kinds of elements can be determined, not only metal elements, but also indirect elements.

Determination of nonmetallic elements and organic compounds by atomic absorption spectrometry.

& lt5> This instrument is simple and easy to operate.

The disadvantage of<6> atomic absorption spectrometry is that it is still difficult to determine many elements at the same time, and there are quite a few elements.

The fixed sensitivity is not satisfactory.