An ultrahigh pressure liquid chromatograph fitting assembly for coupling first and second analytical fluid conduits , the fitting assembly comprising: (a) a first fitting defining a central passage adapted to receive a first fluid conduit defining an internal diameter of no greater than 1,016 mm; (b) a second fitting defining a central passage extending between first and second ends and is in fluid communication with the first fitting ; and (c) a retractable end fitting slidingly secured to the end of the second fitting opposite the first fitting and at least partially disposed within the second end of the second fitting , the retractable end fitting having: (i) a housing; (ii) a tube extending within the housing, the tube having a first end in fluid communication with the first fitting and a second end adapted to receive a second fluid conduit defining an internal diameter of no greater than 1,016 mm; and (iii) a biasing member extending between the housing and a support washer disposed on the tube to allow selective positioning of the tube within the housing relative to the second end of the second fitting to minimize dead space between the tube and the second end , said fitting assembly being characterized in that it comprises (d) at least one pin positioned between the second fitting and the retractable end fitting , said pin being disposed within at least one of an axial groove in the second fitting , and also within at least one of an axial groove in the retractable end fitting , wherein the engagement of said pin with said grooves , prevents rotation of the retractable end fitting relative to the second fitting . (a) a first fitting defining a central passage adapted to receive a first fluid conduit defining an internal diameter of no greater than 1,016 mm; (b) a second fitting defining a central passage extending between first and second ends and is in fluid communication with the first fitting ; and (c) a retractable end fitting slidingly secured to the end of the second fitting opposite the first fitting and at least partially disposed within the second end of the second fitting , the retractable end fitting having: (i) a housing; (ii) a tube extending within the housing, the tube having a first end in fluid communication with the first fitting and a second end adapted to receive a second fluid conduit defining an internal diameter of no greater than 1,016 mm; and (iii) a biasing member extending between the housing and a support washer disposed on the tube to allow selective positioning of the tube within the housing relative to the second end of the second fitting to minimize dead space between the tube and the second end , said fitting assembly being characterized in that it comprises (i) a housing; (ii) a tube extending within the housing, the tube having a first end in fluid communication with the first fitting and a second end adapted to receive a second fluid conduit defining an internal diameter of no greater than 1,016 mm; and (iii) a biasing member extending between the housing and a support washer disposed on the tube to allow selective positioning of the tube within the housing relative to the second end of the second fitting to minimize dead space between the tube and the second end , said fitting assembly being characterized in that it comprises (d) at least one pin positioned between the second fitting and the retractable end fitting , said pin being disposed within at least one of an axial groove in the second fitting , and also within at least one of an axial groove in the retractable end fitting , wherein the engagement of said pin with said grooves , prevents rotation of the retractable end fitting relative to the second fitting . <EOS>