Improved background compensation in atomic absorption spectrometry using the high speed self reversal method

The latest generation of atomic absorption spectrometers allows the quantitation of low and ultralow element concentrations with flame and furnace atomization in a wide variety of different applications. Nowadays, analytical procedures require instruments obtaining reliable and reproducible results with a minimum effort in time-consuming sample pre-treatment. In order to fulfill these items, automatic sampling systems and background compensation techniques are widely used to solve interference problems generated by samples. Furthermore, digital control of heating rates and gas flows as well as intelligent system control allows the accurate and full automatic measurement of multielement sequences up to 20 elements including the changeover of the atomization unit itself. During evaluation of different background compensation methods in flame and furnace operation deuteriumlamp-, high speed self reversal-, and Zeeman- effect based methods have been used. Data have been collected for various samples with typically high background levels. Analytical results for Zn, Cd and As are different according to the selection of the background compensation method. Additionally, differences in sensitivities must be considered. Problems and limitations of the deuterium background compensation method will be discussed and compared with experimental data generated using the high speed self reversal method and literature data.