To confirm the accuracy of the analysis technique another sample/batch of Cyt C and Zn Porph functionalized sample (AuNP-PEG-Cyt C/Zn Porph-S2) with a more complex Soret band peak was deconvoluted (Figure ). When the Soret band of Figure is compared to Figure , it appears as a different shape with shoulders on each side of the peak. In this case, fitting the deconvoluted spectrum with just two components resulted in a large RSD suggesting the presence of another component. Therefore, the third component at 423 nm which corresponds to the absorption peak of free unconjugated Zn Porph (Fig ) was added to improve the fit. The fitting resulted in an RSD of 0.002 (Figure ). The inclusion of a third component supposes that free/unconjugated Zn Porph is still present in the solution together with Zn Porph conjugated to AuNPs. Therefore, suggesting further purification of the sample is required. Interestingly, the formation of Zn Porph Jaggregates can also be identified using this method, which is of great importance as the fluorescence properties of porphyrins depend on their aggregation state and local environment. This can also be done by deconvoluting the UV-visible absorption absorption spectra of free Cyt C OX and Zn Porph in water (Figure ). Based on the above observations it is evident that this analysis is essential and should be performed regularly to every batch of samples together with UV-visible absorption spectroscopy for accurate quantification of bound molecules, especially in applications such as drug delivery where UV-visible absorption is often used to quantify surface conjugated molecules.