In the previous investigation, data has been collected in order to evaluate the effect of matrix modification on reduction of molecular absorption, a spectral interference commonly associated with graphite furnace atomic absorption spectrometry. Absorption signals due to absorbance of molecules, either from the AHF sample matrix or molecules containing aluminum result in an enhancement of the atomic absorption signal for aluminum in AHF when compared with an aqueous standard of the same concentration. Matrix modification of antihemophilic factor (AHF) has been accomplished through the addition of the non-ionic detergent Triton X-100 and sulfuric acid. Analysis of accumulated data thus far obtained, has shown that modification results either in an increase in the volatility of matrix components or a decrease in the volatility of aluminum such that the matrix components responsible for background absorption are more easily eliminated during thermal pretreatment steps of AHF prior to atomization thus leading to more accurate and precise analysis. In AHF it is often difficult to prepare standards that are sufficiently similar to the sample solution. This occurs when samples such as AHF contain variable concentrations of matrix materials whose effect on atomization/absorption is difficult to replicate. A study is currently being undertaken to evaluate the efficacy of multiple standard addition in order to correct for nonspectral interferences. Analysis of data collected to date shows this technique to be an accurate method of calibration. Future studies involving the use of multiple standard addition as a calibration technique will focus on recovery and reproducibility of added aluminum in AHF. In addition, another objective of this study is to develop atomic absorption spectrophotometric (AAS) methodology for the quantitative analysis of aluminum in various adsorbed toxoids, vaccines and alum precipitated allergenic extracts. Mass spectrometry will be explored as a method of determining structural information for the aluminum adjuvant-antigen complexes in the various adsorbed vaccines.
