Charged particle separation by the dE/dx method in a liquid krypton (LKr) ionization chamber has been experimentally studied. The detector has been exposed to pions and protons at the T11 test beam of the CERN PS. Results on particle separation at three different energies are presented. Some results on the performance of monolithic preamplifiers purposely developed to be employed at cryogenic temperatures in calorimetry applications are also presented.