Abstract: Disclosed herein, among other things, are methods and apparatus related to radio frequency (RF) ablation catheters. The present subject matter provides an ablation catheter system including a catheter body with a distal tip, and a thermocouple component at the distal tip. The thermocouple component is adapted to sense temperature of bodily fluid and/or tissue. The system includes a non-conductive insert configured to physically separate and thermally insulate the thermocouple component from the catheter body. Various embodiments include an open-irrigated ablation catheter system, the system further including at least one fluid chamber and a plurality of irrigation ports within the catheter body, where the plurality of irrigation ports enable fluid to exit from the at least one fluid chamber. The non-conductive insert is further configured to physically separate and thermally insulate the thermocouple component from the plurality of fluid flow channels and irrigation ports.