Quantitative Methodology

Such as several other analytical methods, AAS is also not an absolute method of analysis. The routine analytical methodology for quantitative determinations using AAS is based on calibration method. Besides this, the internal standard techniques and standard addition methods are also employed.

Calibration plot method

In this technique, a calibration plot is drawn through aspirating standard solutions of known concentration within the flame and measuring absorbance for every solution. The concentration of the unknown solution is then denotes from the calibration plot. Despite the fact that Beer's law is followed within AAS, in practice the departures from linearity are encountered as displays in Figure. The nonlinearity is because of the transmission of unabsorbed light from the radiation source. Further, a number of uncontrolled variables within atomisation and absorbance measurements might also affect the measurements. Thus, we required to search the concentration range in that the Lambert-Beer's law holds that is we get a straight line.

Figure: Typical calibration plot between the absorbance and the concentration of analyte element