Depth profiles of organic delta layer standards show that the depth accuracy and resolution is dependent on the secondary ions used as well as the primary ions and their energy. Without standard samples comprising molecules from the LNPs, it is difficult to differentiate broadening due to sputter effects from actual concentration gradients representing component intermixing or heterogeneous particle chemistries. Therefore, the depth resolution expected on these spherical, real-world frozen hydrated LNP samples is difficult to estimate, although sputter profiling of nano particulate geometries has been studied for welldefined gold and silica particles where the degradation of the depth content was quantified, this is likely not to transfer directly to the organic self-assembled particles considered here. We have therefore been cautious in our quantitative interpretation of the LNP depth profiles.