A fitting assembly having a single- or double-headed ferrule, a nut, and a fitting that may be assembled or dissembled by an operator. The fitting assembly includes a nut with first and second ends, with the second end adapted to receive or abut the first end of a ferrule, and further includes a fitting with a first end having an internally tapered portion adapted to receive the second end of the ferrule and a second end adapted to be removably connected to a component or fitting of a liquid chromatography system. The nut, ferrule and fitting of the fitting assembly have passageways therethrough for receiving and removably holding tubing.