An electrochemical reactor and process for electrolyzing a substance to change at least a portion of the substance from a first state to a second state. The reactor comprises a tubular body having a first end portion defining an opening and a second end portion defining an electrolysis chamber. The electrolysis chamber includes a well adapted to hold the substance and at least two electrodes for electrolyzing the substance in the well. The volume of the well is less than about 3 milliliters. The reactor further comprises a coupling for releasably and sealingly connecting the reactor body to an auxiliary device body. The coupling is adapted to provide a vacuum tight seal between the reactor body and the auxiliary device and to allow the reactor body to rotate about an axis of rotation independent of the auxiliary device while the reactor body is sealingly connected to the auxiliary device.