The principle is to quantitatively inject the sample into a graphite tube using a sampler, and use the graphite tube as a resistance heating element. After being energized, the sample quickly heats up to achieve atomization. The heating power supply, maintenance gas control system, and graphite tube furnace are composed. An external power supply is added to both ends of the graphite tube to supply energy to the atomizer. The current flows through the graphite tube to generate a temperature of up to 3000 ℃, causing the measured element in the graphite tube to become ground state atomic vapor. The maintenance gas control system is used to control the instrument startup of maintenance gas, maintain the flow of Ar gas, and cut off the Ar gas flow after the air combustion is completed. The Ar gas in the external gas path flows along the outer wall of the graphite tube to maintain it from being burned, while the Ar gas in the internal path flows from both ends of the tube to the center of the tube and flows out through the center hole of the tube to effectively remove the matrix vapor generated during the drying and ashing processes, while maintaining that the atomized atoms are no longer oxidized. During the atomization stage, ventilation is stopped to extend the average residence time of atoms in the absorption zone and prevent dilution of atomic vapor. In the graphite furnace atomization system, the flame is replaced by an electrically heated graphite tube placed in an argon atmosphere. Argon gas can prevent rapid oxidation of graphite tubes at high temperatures and remove matrix components and other interfering substances from the optical path during the drying and ashing stages. A small amount of sample (1 to 70mL, usually around 20mL) is added to the pyrolytic coated graphite tube.

The pyrolysis coating on the graphite tube can effectively prevent oxidation of the graphite tube, thereby extending the service life of the graphite tube. At the same time, the coating can also prevent the sample from invading the graphite tube, thereby improving sensitivity and repeatability. The graphite tube is heated by an electric current, and the magnitude of the current is controlled by a programmable control circuit. Therefore, during the heating process, the sample in the graphite tube can be heated using a series of heating methods to remove the solvent and most of the matrix components, and then atomize the sample to form ground state free atoms. The decomposition of molecules depends on factors such as atomization temperature, heating rate, and the surrounding environment of the hot graphite tube wall.