Versus electrothermal atomizers

In analytical spectrometry there are many types of calibration curves which are set up by measuring spectrometric reference solutions. The measurements yield a curve of absorbance versus concentration, and the points between the data of the reference solutions are interpolated by fitting a suitable curve, which normally follows the Beer-Lambert law and which gives rise to a straight line through the origin of the coordinate system. The measurement conditions and the results of the calibration curve evaluations in the case of chromium and lead measurements by electrothermal atomic absorption spectrometry are presented in Table 1. 

The display of signal versus time curves in real time is very important for the development of analytical procedures. In atomic absorption spectrometry with electrothermal atomization this is now indispensable and is an integral part of the development of an analytical procedure to be applied for a given analytical task. It is of further importance during the optimization of the plasma working parameters in ICP-AES and is certainly very useful for the optimization of the spectrometer with respect to drift and as a result of changes in any of the working parameters. 

Most commerical electrothermal atomizers based on the L vov furnace as simplified by Massman (3) and undergo vigorous changes in tube temperature. The analyte atoms volatilized from the tube wall come into a eooler gas, so that molecular species that are not detected are formed. This leads to what is termed matrix interferences. For example, equal concentrations of Pb + in a matrix of deionized water versus one of high chloride content would yield different absorbances. One way to remove this chloride matrix interference is to use a matrix modifier. The addition of an ammonium salt to the chloride-containing matrix would cause volatilization of NH4CI with removal of chloride from the sample matrix. 

---