Within this thesis, a method for the quantification of fluorine in biological, phosphate-rich matrices was established using high-resolution continuum source (HR-CS) molecular absorption spectrometry (MAS). The optimization of the procedure was accomplished by employing a multivariate approach based on experimental design technique. A highly sensitive method was developed, while interferences due to the complex phosphate-rich matrix were completely eliminated. The procedure is suitable for pharmacological testing of fluorine-containing drug candidates, based on the concept of utilizing covalently bonded fluorine as a probe for indirect determination of the fluorinated drug compound. Subsequently, the HR-CS MAS method was applied to the biological characterization of antitumor-active fluorinated metal complexes. On the one hand, the results of these studies provide basic knowledge concerning their pharmacological properties. On the other hand, structure-activity relationships could be established, which are a sound basis for further development of the respective classes of compounds.