The basic components of any type or brand of atomic absorption include the following:
A- Light Source
D- Photomultiplier Detector
E- Output Device
The primary sources of radiation in atomic absorption are hollow cathode lamps. These lamps are composed of a cathode and an anode sealed in a tube with an inert gas (argon or neon). The cathode is made of the element to be determined. When a high voltage is applied the atoms of the inert gas are ionized and attracted by the cathode. These ions hit the cathode and excite the atoms of the elements used to make the cathode. Once the atoms are excited radiation is emitted at the characteristic wavelength of the element. The light from the hollow cathode lamp passes through the flame (Burner/nebulizer) where the sample is atomized. This fine mist of the sample is sprayed into the nebulizer. Atoms of the elements are formed from the sample mist and are able to absorb some of the light from the lamp at the wavelength set for that particular element. The light passed through the flame is received by the monochromator, which is set to accept and transmit radiation at the specified wavelength. The light emerges from the monochromator exit slit and falls on the photomultiplier detector. At this point an output current, proportional to the incident light, is intensified, amplified, processed electronically and finally presented to a readout device (i.e. printer, digital display).