Nitrous oxide / acetylene flame absorbance spectrum

Since shortly after its inception in 1955, AAS has been the standard tool employed by analysts for the determination of trace levels of metals. In this technique a fine spray of the analyte is passed into a suitable flame, frequently oxygen-acetylene or nitrous oxide-acetylene, which converts the elements to an atomic vapour. Through this vapour is passed radiation at the right wavelength to excite the ground state atoms to the first excited electronic level. The amount of radiation absorbed can then be measured and directly related to the atom concentration a hollow cathode lamp is used to emit light with the characteristic narrow line spectrum of the analyte element. The detection system consists of a monochromator (to reject other lines produced by the lamp and background flame radiation) and a photomultiplier. Another key feature of the technique involves... 

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