GC Column Change Procedure

GC Shutdown

On the TotalChrom menu, press run and clear setup icon.
Click on Run icon followed by “release control”.
Click on Run icon followed by and detach.
Now click on Admin menu, then “cam administration”, click on users, followed by manager.
Highlight item that has “Clarus” in it, and then click on edit menu, followed by remove locks. Make sure that all items with Clarus have been removed.
Now the computer and GC are detached and GC can be operated by itself.
Shut off power for the Clarus GC.

Column Removal

Hydrogen, helium and air valves back of the GC need to be off.
After GC oven is cooled, remove the old column.
Remove nuts at each end of the column for reuse.
Remove the septum nut and gas line nut.
Remove the injection port glass liner by pushing the thin rod in the injection port cavity from inside the oven.
Glass liner and an “O” ring will come out from the top. Examine the “O” ring, if looks worn out replace it. If glass liner looks dirty, replace it.

Column Installation

A. Use the same column

If overall chromatogram is O.K. but some peaks show tailing or not seen, unravel about a turn and a half of column at each end. Cut ~ 6-12 inches of each end. Install the column into GC as per directions in step C.

B. New Column

Take out new column from the box. Unravel about a turn of column at each end, cut ~3-4 inches of each end. Install the column into GC as per directions in step C.

C. Install column in GC

Each end of the column needs to stick out ~10 inches beyond the column cage.
Insert small nut at the thick end of the column, followed by injection port ferrule. The tapered end of the ferrule goes first inside the 1/16 inch nut.
Now insert 1/8 inch nut into the thin end of the column. Ferrule has a tapered end and small diameter protruded end. The protruded end goes inside the nut first.
Now insert the thicker diameter column with small nut end into injection port.
Insert the thinner diameter column with big nut into detector end.
Loosely tighten both nuts.
Each end of the column should be visible and sticking out on the top of the instrument. If not take column out, unravel some more columns and repeat the steps shown above.
Cut the column on injector side approximately flush with the outside port surface.
Insert glass liner with “O” ring over the column end. Push the liner down to make it flush with the outside port surface.
Insert gas line nut and tighten it.
Inside the oven, push the column upward, till you feel resistance. Tighten the nut snugly by hand, followed by approximately ¼ turn by wrench.
Replace septum in the nut and place septum nut on.
On detector end, cut column about ½ inches above the detector surface.
Now push column up about 3 inches, and cut it again.
Pull back the column about 2 inches or so.
Insert wooden dowel in the detector cavity and let it rest on the detector cavity.

Push column slowly up and see that it pushes the dowel up.
Pull back column so that it does not push dowel, NOW PULL BACK another ~1/2 inches. Tighten the nut snugly by hand, followed by approximately ¼ turn by wrench.
Remove the dowel.

GC Startup

Turn on all three gases followed by power switch. Log on to GC.
Ignite the flame for the detector.
Go to GC, inject one microliter of heptane and make sure you see big large peak within 30 seconds.
On TotalChrome software, click on run, followed by attach icon for the Clarus GC.
Click on run, followed by take control icon. Now GC is controlled by computer.
Go to the setup and type in next six lines as standard #5, run # 1, 2,3,4,5 and 6.
Under modify the sequence, for the first run (run #1), choose Biodiesel conditioning method. It allows to conditioned column faster and better.
First few runs will have few extra peaks and upward drifts in baseline. As column gets conditioned, baseline will get smoother. Last three runs or so will be consistent.

USP 2021 (United State Pharmacopeia 44 - NF 39)