Key concepts
A hollow-cathode lamp emits narrow lines characteristic of one element. The nebulizer carries sample into the flame, where droplets become free ground-state atoms. Matching photons are absorbed and excite electrons to higher energy states.
For suitable conditions, absorbance increases approximately in proportion to concentration and optical path. The monochromator isolates the analytical line before the detector measures transmitted light.
Applications & misconceptions
Applications: drinking-water metals, clinical samples, food minerals, soils, alloys, and environmental monitoring.
Misconception: The detector does not directly count sample atoms. It measures how much resonant light remains after the atom cloud.