The number of Cyt C and Zn Porph molecules per litre can also be found by first calculating their concentration and subsequently the number of molecules per AuNP. For the concentration, the height of the deconvoluted peaks was found by subtracting the background from the spectra. The absorbance peak heights were then divided by the extinction coefficients of Cyt C (101600 M -1 cm -1 ) and Zn Porph (57940 M -1 cm -1 , calculated from a concentration curve in Figure ), resulting in the bound concentrations. The concentration of Cyt C for the AuNP-PEG-Cyt c/Zn Poprh sample (Figure ) was calculated to be 0.42 µM, which corresponds to 2.53´10 Cyt C molecules per litre. Similarly, the concentration of Zn Porph for AuNP-PEG-Cyt c/Zn Poprh sample (Figure ) was calculated to be 1.30 µM, with a subsequent 7.83´10 Zn Porph molecules per litre. By dividing the number of molecules of Cyt C and Zn Porph per litre by the number AuNPs per litre, the quantity of each molecule was calculated to be 346 and 1073, respectively. The AuNP concentration of the AuNP-PEG-Cyt c/Zn Poprh-S2 (Figure ) was calculated to be 0.26 nM, with 1.55´10 14 AuNPs per litre. The concentrations of Cyt C and Zn Porph were calculated to be 0.40 µM and 1.16 µM, equating to 2.4´10 17 and 6.99´10 17 molecules per litre respectively. Thus, the number of molecules bound to each AuNP was calculated to be 1545 Cyt C and 4500 Zn Porph. The Zn Porph free solution in this sample was also calculated to have a concentration of 1.11 µM. The quantity of conjugated molecules in Figure is over four-fold the quantity of conjugated in Figure , suggesting that the Zn Porph free in solution is hindering the accurate determination of the number of molecules bound to the AuNPs. Deconvolution of peaks on multi-functional AuNPs, therefore, provides users with valuable information about the quality and concentration of their conjugated molecules, while also providing insight into whether their material needs to be purified further.