Atomic fluorescence spectrum is an emission spectrum produced by atoms absorbing radiation and raising to an excited state, then returning to the ground state or another energy state adjacent to the ground state, and releasing the absorbed energy in the form of radiation in all directions. Taking sk-2003a as an example, the sample solution and reducing agent to be measured enter the multi-functional reaction module for hydrogenation reaction using patented continuous flow sampling technology, and the waste liquid is automatically discharged in a pressure self-balancing manner. After the reaction, the hydride gas of the element to be measured is , argon and hydrogen are transferred to the expansion transfer chamber and mixed thoroughly before entering the atomizer. The unstable hydride is separated to obtain the ground state atoms of the element being measured. It is excited by the light source to emit fluorescence, and the fluorescence intensity is detected to obtain the sample concentration.