Locate the tubing in the HPLC that connects the injection valve to the inlet of the HPLC column. This tube will be made of stainless steel or PEEK, and is referred to as the column inlet tube or column inlet line.
If the end of the column inlet tube that goes into the HPLC column is bare, with no nut and ferrule, place a stainless steel male nut (10-32 threads) for 1/16 OD tubing, over the tubing at the end where the tube goes into the inlet of the column with the threads facing toward the open end of the tube.
Place a stainless steel compression ferrule over the tube in front of the stainless steel nut so that the tapered end is facing toward the open end of the tube.
Using a 3/8" open end wrench to hold the inlet of the HPLC column, use a 1/4" wrench to tighten the stainless steel male nut with the ferrule in front of it while firmly inserting the tube into the open end of the HPLC column fitting. Ensure that the tube is seated in the bottom of the fitting with no gap.
Tighten the nut until it is snug, about 1/4 of a turn with the 1/4" wrench.