Fractional desorption spectroscopy (FDS) is an interesting new approach for the determination of activation energies for a large range of surface processes. The activation energy can be determined over a wide coverage range using a single experiment. The FDS method utilizes a modulated temperature program during the desorption experiment by applying a modified Arrhenius analysis to extract kinetic parameters from desorption rate vs temperature data. FDS improves on other differential approaches in two important aspects. First, it enables determination of the activation energy over a range of accessible surface concentrations in a single adsorption/desorption experiment. This is particularly useful for studying surface reactions involving multiple species or in cases where complex surface preparations an required prior to the temperature-programmed desorption (TPD) experiment. Second, the FDS method possesses unique self-diagnostic and system-diagnostic abilities. The self-diagnostic aspect of the method enables a more systematic approach to eliminating errors from baseline drift. Like other differential approaches, the FDS method does not require assumptions about the reaction order, frequency factor, or the dependence of activation energy on surface concentrations. In this paper, the FDS method is shown effective in estimating concentration-dependent activation energies for first-order desorption, second-order desorption, and binary surface reaction processes, using straightforward desorption models. We experimentally validate the FDS method by applying the technique to determine the activation energy for CO desorption, O atom recombination and desorption, and CO2 formation from adsorbed CO and O atoms, all on the Pt(lll) surface. The FDS-determined activation energies for these systems are in excellent agreement with values established in the literature.