nebulizer
/ NEB-yuh-ly-zer /
A nebulizer is the part that turns a liquid sample into a fine mist, like a perfume atomizer or an asthma inhaler. A flame or plasma cannot swallow a stream of liquid; it needs the sample broken into a cloud of tiny droplets so small they can ride the gas flow straight into the heat.
More precisely, the sample solution is drawn up a fine tube and met by a fast jet of gas that shears it into an aerosol. A spray chamber then filters out the larger droplets and lets only the finest ones through to the atomizer, because only droplets small enough to evaporate completely will release their atoms in time.
It matters because the nebulizer is the gateway between liquid sample and free atoms; its efficiency and steadiness set how much signal you get and how repeatable it is. The honest caveat is that ordinary nebulizers waste most of the sample in the spray chamber and clog easily on salty or particle-laden solutions.
In a flame AAS, the sample is sucked up and sprayed by a pneumatic nebulizer; the spray chamber drains away the big droplets, and only a fine mist — perhaps a tenth of the sample — actually reaches the flame to be atomized.
Liquid in, mist out — only the finest droplets reach the flame.
Nebulization is the first stage of getting a liquid into the source; atomization is what happens afterward in the heat. The graphite furnace skips the nebulizer entirely, placing a measured drop of liquid directly into the tube.