The simplest amino acid, glycine, has recently been identified on the comet Churyumov–Gerasimenko (67P) [Altwegg et al., 2016]. Independent on how this and likely other amino acids have been formed - in-situ or inherited along the different chemical stages during comet formation in the Solar Nebula - the ice embedded amino acids have been exposed to radiation, including vacuum ultraviolet (VUV) radiation. We have systematically investigated in the laboratory the effect of VUV radiation (120-200 nm) [Ligterink et al. 2015] on glycine and phenylalanine at two low temperatures (10 & 100K) intimately mixed in water ice, as water is the most abundant ice in comets, on icy moons and interstellar dust grains. We present a new method to study the VUV photo-stability of amino acids in water ice and demonstrate the protective properties of water ice, as well as its effect on the photo-chemistry of amino acids [Bouwman 2009, et al. Kofman et al. in prep.]. The preliminary results indicate that water layers thicker than a few hundred nm are well capable of providing sufficient protection from VUV radiation to preserve amino acids, fully in line with the observations from the ROSETTA mission.