To prove the robustness and reproducibility of this method another example of Soret band deconvolution was conducted on the sample with a closer overlap in 50 nm AuNPs (Figure ). The Soret band of 50 nm cit-AuNPs functionalized with HS-PEG-COOH, Cyt C and a non-metalated porphyrin (Porph, structure in Figure ) appears as a single peak. The maximum Soret band absorbance of Porph at 415 nm shows a greater overlap with reduced Cyt C (lmax = 415 nm) (Figure ) than that Zn Porph at 423 nm, therefore individual component concentrations cannot be calculated from the convoluted peak. The deconvolution enables the concentrations of Cyt C and Porph mixed free in solution (Figure ) to be calculated as 2.12 µM and 2.65 µM respectively, closely matching the 2.5 µM theoretical concentration of the prepared solutions. For 50 nm AuNP-PEG-Cyt C/Porph the concentrations of Cyt C and Porph were determined to be 0.11 µM and 0.17 µM respectively. The coverage of Cyt C and Porph per AuNP was 23,259 and 35,168 respectively (Table ). The higher number of molecules per AuNP is due to the lower concentration of AuNPs in the sample and their larger diameter.