Spectrometry with transmitted light

More than 70 elements can be measured by AAS (Figure 13.18). The lowest concentration that can be quantified in a sample depends upon many factors. In spectrometry the sensitivity for an element is defined as being the concentration expressed in pig/L which, in aqueous solution, leads to a 1 per cent decrease (A = 0.0044) in the transmitted light intensity. So, for manganese (Mn), this value is 4pg with an aqueous matrix. When possible, a calibration curve should be established with concentrations in the range of 20 to 200 times this value. 

The application of atomic absorption spectrometry to quantitative analysis is illustrated in Figure 2.2. The incident radiation at resonance wavelength with intensity /q is focused on the flame containing the atoms in their fundamental state and is transmitted with a reduced intensity I determined by the concentration of the atoms in the flame. The radiation is directed to the detector where the intensity is measured. The quantity of absorbed light is determined by comparing / to /q. 

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