Multilayer GNPs have a higher graphitic volume to surface area than single and few-layer graphenes, reducing the sensitivity of spectroscopy techniques to changes in the surface chemistry. Furthermore, the heterogeneity of flakes sampled by the Raman laser, leads to significant spectral variance that can be lost when observing an average spectrum. In Box plots for peak fit parameters associated with the D, G and 2D modes, as well as their intensity and amplitude ratios.