Extension of the dynamic range by using an atom formation function in electrothermal atomic absorption spectrometry

Abstract

A method of extending the dynamic range of a calibration graph by calculating the initial mass of an analyte on a tungsten strip heater using an atom formation model in electrothermal atomic absorption spectrometry is proposed. The model is based on the assumption that the rate of atom formation, given by a simple Arrhenius-type expression, is a function of the number of atoms in a sample on the heater and the heater temperature. The absorbance for the initial mass of iron chosen as a test analyte was obtained by applying the absorbance at the initial stage of the signals to the model equation, and the calculated values of the mass were plotted against the amount of iron in the test solution to give a calibration graph. To extend the dynamic range further, the light beam from a hollow-cathode lamp was adjusted so as to pass through a region of low atom density above the heater.