Understand the structure, application and detection standards of AAS of atomic absorption spectrometer in one article.
Atomic absorption spectrometer (AAS) is an analytical instrument based on the principle of atomic absorption, which is used to determine the content of specific elements in a sample. AAS utilizes an atomizer to convert the elements in a sample into an atomic state, and then emits a specific wavelength of light through an excitation light source, causing the atoms to undergo excitation and transition to a higher energy levelWhen these excited atoms return to their ground state, they emit light of a specific wavelength, which is captured by a detector to analyze the concentration of elements in the sample.
1. AAS structure.
The atomic absorption spectrometer is mainly composed of the following five parts:
1.Excitation light source: The characteristic spectrum of the element being measured is emitted, usually a sharp light source, such as a hollow cathode lamp (HCL) or electrodeless discharge lamp (EDL).
2.Atomizers: Convert elements in a sample into atomic vapors, including flame atomizers and flameless atomizersThe flame atomizer is mainly composed of a burner head and an atomizer, and the flameless atomizer includes a graphite furnace atomizer and a hydride generator.
3.Spectroscopic system (monochromator): separate the spectral lines (or resonance lines) of the measured element, which are composed of slits, lenses, mirrors, gratings and other parts.
4.Detection and control system: The detector is used to complete the conversion of photoelectric signals and convert optical signals into electrical signals. The commonly used detector is the photomultiplier tube, and in recent years, solid detectors such as area array CCDs have also begun to be used. The control system is used to coordinate the work of various components of the spectrum, and most of the AaaS is controlled by a single-chip microcomputer or a general-purpose PC.
5.Data processing system: used to process the detected signal and perform data analysis.
In addition, there are some additional systems, such as background correction system, atomizer cleaning system, etc.
2. AAS application.
AAS has a wide range of applications in many fields, including:
1.Environmental monitoring: detect heavy metal elements in air, water, soil, such as lead, cadmium, mercury, etc.
2.Chemical reagent analysis: determine the metal ion content in the reagent to ensure the purity and quality of the reagent.
3.Metallurgical industry: analyze the elemental composition of steel and non-ferrous metals to improve product quality.
4.Pharmaceutical field: detect the content of metal elements in drugs and biological samples to ensure the safety and effectiveness of products.
5.Food and cosmetics industry: analysis of harmful elements in food and cosmetics to protect the health of consumers.
6.Geology and minerals: exploration of mineral deposits, analysis of elemental composition in rocks and minerals.
3. AAS testing standards.
The testing standards of AAS mainly include national standardizers and industry standards, such as:
1.GB T 7475-1987 "Water quality - Determination of copper, zinc, lead and cadmium - Atomic absorption spectrophotometry".
2.GB T 15337-2008 General Principles of Atomic Absorption Spectroscopy Analysis
3.GB T 9723-2007 Chemical Reagents – General Principles of Flame Atomic Absorption Spectrometry
4.GB T 23768-2009 General Principles for Flame Atomic Absorption Spectrometry for Inorganic Chemical Products
5. gb/t 17593.1-2006 "Determination of Heavy Metals in Textiles - Atomic Absorption Spectrophotometry".
6.HJ 751-2015 "Solid wastes - Determination of nickel and copper - Flame atomic absorption spectrophotometry".
7.GB 36246-2018 "Single Judgment of Test Result Limits for Test Items of Synthetic Material Surface Sports Fields for Primary and Secondary Schools".