Abstract: Improved capillary electrophoresis (CE) apparatus (10) is provided which includes an intermediate grounding joint (34) serving to isolate delicate electrochemical detectors (32, 54, 58) from the high voltage CE power supply (20). The joint (34) includes a fracture (36) close to the detection end (22) of the apparatus (10) which is covered by a Nafion sleeve (38). The joint (34) is immersed in an ionic buffer reservoir (46) which includes a grounded cathode (48). In fabrication procedures, a capillary tube (12) is scored in proximity to one end (22) thereof, and the Nafion sleeve (38) is slid over the score line. The sleeve (38) is then sealed with epoxy (40, 42) at the ends thereof.