The concentration of biomolecules on functionalized AuNPs is commonly determined using bioassays suhch as ELISA, or less common techniques such as ToF-SIMS. The analytical methodology to determine the exact concentration of each functional molecule in a multifunctionalized material is not often thoroughly described. Furthermore, analysis of multifunctionalized AuNPs by UV-visible absorption spectroscopy is complicated by the molecular complexity caused, for example, by similarity in the absorption spectrum of the conjugated molecules such as porphyrins and proteins like Cyt C that could lead to erroneous calculated numbers.