Is the 3.5 μm infrared feature on Enceladus due to hydrogen peroxide?

We use new and previously published measurements from our laboratory to examine the assignment of a 3.5 μm feature in the infrared spectrum of Enceladus. The spectral feature, taken with Cassini's VIMS Spectrometer, has recently been interpreted as an absorption band from hydrogen peroxide on the surface. Such identification is important because it would imply an intense flux of magnetospheric particles, which are thought to be required to produce H ₂O₂ from surface water ice. We compare the position and width of this feature with measurements of infrared spectra of water-hydrogen peroxide mixtures. We conclude that the reported feature from Enceladus does not correspond to hydrogen peroxide.