The primary objective of this project is to develop methodology for the quantitative analysis of aluminum in injectable biological products that contain aluminum, either, as a result of inadvertent contamination or through intentional addition. Earlier project objectives were directed toward the evaluation of the effect of sample matrix modification in combination with Zeeman-effect background correction on the reduction of molecular absorption, a spectral interference commonly associated with electrothermal atomic absorption spectrometric analysis. In addition, the technique employing multiple standard addition has been evaluated for its abililty to correct for non-spectral interferences. Since the initiation of these earlier projects, there have been many improvements in the basic design of electrothermal atomizers. Limitations were often associated with earlier designs. Most commonly, the temperature distribution along the electrothermal atomizer was not uniform due to contact of atomizer tube ends with water cooled contact cylinders. This inevitably would cause memory effects as a result of matrix condensation at the cooler ends of the atomizer tube. The goal of the current project is to utilize new developments in the basic design of the electrothermal atomizer in order to further develop analytical methododogy for aluminum determination and characterization. This new atomizer design specifically involves a transversally heated graphite tube as opposed to a longitudinally heated one. This design improvement will provide a more uniform temperature distribution over the entire tube length i.e. the atomizer tube ends will reach the same temperature as the tube center during the atomization stage. Under these conditions, the formation of free atoms will be optimal, molecular formation from atoms will be decreased, the loss of atoms will be minimized, and condensation at the cooler tube ends, which can produce memory effects, will be substantially eliminated. These new developments involving electrothermal atomizer design, is currently being employed in the evaluation of the accuracy, precision and robustness of analytical methodology that has been developed for aluminum determination and characterization in human plasma fractionation products.
