1) The elements must be reduced to the elemental, neutral ground state by the flame. 2) The elements must be in vaporized state. 3) The elements must be imposed in the beam of radiation from the source. Advantages: Very sensitive. Fast. Disadvantages: Hollow cathode lamp for each element. Expensive element.1) The elements must be reduced to the elemental, neutral ground state by the flame. 2) The elements must be in vaporized state. 3) The elements must be imposed in the beam of radiation from the source. Advantages: Very sensitive. Fast. Disadvantages: Hollow cathode lamp for each element. Expensive element