Spectroanalysis, the principle of spectral analysis

Spectroscopic analysis: A method of identifying substances based on their spectrum.

The three commonly used spectroscopic analysis methods are as follows:

Spectroscopy refers to a class of analytical methods for substances, mainly including atomic emission spectrometry, atomic absorption spectroscopy, ultraviolet-visible absorption spectroscopy, infrared spectroscopy, etc.

Spectroscopy can be further divided into molecular spectroscopy and atomic spectroscopy. It is mainly produced by the jump of valence electrons in the molecule, so this absorption spectrum is determined by the distribution and binding of valence electrons in the molecule. Spectroscopy has the advantages of fast analysis speed, easy operation, no need for pure samples, simultaneous determination of multiple elements or compounds, good selectivity, high sensitivity, and less sample damage, but of course it also has certain limitations.

For example, spectral quantitative analysis should be based on relative comparison, there must be a set of standard samples as a benchmark, and the composition and structure of the standard samples should be basically consistent with the samples being analyzed.

The molecular absorption spectrum produced by the absorption of electromagnetic radiation energy in the range of 200 760nm is called the ultraviolet-visible absorption spectrum of the substance, and the method of qualitative and quantitative analysis of the substance by using the ultraviolet-visible absorption spectrum is called ultraviolet-visible spectrophotometry. The spectrum is due to the jump of valence electrons in the molecule, so this absorption spectrum is determined by the distribution and binding of valence electrons in the molecule.

It is widely used in the field of feed processing and deterioration, especially in the determination of the content of lead, iron, lead, copper, zinc and other ions in feed. Fluorescence analysis is also a trace analysis method that has developed rapidly in recent years, which is simple, rapid, sensitive, precise and accurate, and has a wide linear range and low detection limit.

The principle of spectral analysis is a means to obtain the structure, composition and property information of substances by using the interaction between substances and Naidan cherry light to study the absorption, scattering, emission and other characteristics of different wavelengths of light by substances.

In spectroscopic analysis, commonly used methods include atomic absorption spectroscopy, atomic emission spectroscopy, molecular absorption spectroscopy, Raman spectroscopy, fluorescence spectroscopy, etc. Among them, atomic absorption spectroscopy and atomic emission spectroscopy are the two most common spectroscopic analysis methods.

Atomic absorption spectroscopy uses the principle that atoms in a substance absorb light at a specific wavelength to produce characteristic absorption spectral lines to determine the content and presence of certain elements in a sample. Atomic emission spectroscopy, on the other hand, uses the emission spectral lines of a specific wavelength generated after the excited atoms to identify and analyze the elements in the sample.

Molecular absorption spectroscopy is to dissolve or dilute the sample, use visible light or ultraviolet light to irradiate the sample, and measure the degree of light absorption by the sample to identify and analyze the compounds in the sample.

Characteristics of spectral analysis:

1. High sensitivity: Spectral analysis technology can achieve very high sensitivity and can detect very small changes in the concentration of substances.

2. High resolution: The absorption, emission and scattering characteristics of light by different substances will present unique spectral images, and spectral analysis can be carried out quantitatively and qualitatively through the analysis of these characteristics.

3. Non-destructive: Compared with other chemical or physical analysis methods, spectral analysis is a non-destructive analysis technique, and the sample does not need to be destroyed or the structure can be tested.

4. Multi-element detection: Spectral analysis can detect a variety of elements and compounds at the same time.

5. No sample preparation required: In some cases, spectroscopic analysis does not require any processing or preparation of the sample to complete the test.

1 Pinyin 2 Annotations.

guāng pǔ fēn xī

Spectroscopy is an abbreviation for spectrochemical analysis. An analytical method for determining the composition of a substance based on the spectral beam in which it occurs. Spectra can be divided into emission spectra and absorption spectra.

The former is produced by direct excitation of flames, arcs or electric sparks or by taking the specimen. The wavelength of the characteristic spectral line is used to determine the type of element contained in the measured substance, which is called spectral qualitative disorder analysis. The intensity of the characteristic spectral lines is used to determine the number of elements contained in the measured substance, which is called spectral quantitative analysis. The method is extremely sensitive and accurate.

The latter is the light absorbed and produced by the substance being measured. According to the different wavelengths of the light source, it can be divided into visible absorption spectrum, ultraviolet absorption spectrum and infrared absorption spectrum. Spectroscopic analysis is often used for the analysis of chemical components of traditional Chinese medicines.