Whether your GC instrument has only been shut down for a couple of days or has been gathering dust in a corner for a year, follow CHROMacademy's quick checklist to increase performance and reliability.
Modern GCs are simple and very reliable instruments, with virtually no moving parts. As such, problems relating to faults with the instrument are rare. As troubleshooting GC problems can be difficult, the secret to reliable performance lies in taking the time at the start to set up the instrument correctly. Whether your GC instrument has only been shut down for a couple of days or has been gathering dust in a corner for a year, follow our quick checklist to increase performance and reliability.
Turn on the cylinders. Is the cylinder bottle pressure is less than 30 psi? Replace the cylinder.
Verify that the gas filters haven’t been exhausted and check when they were last replaced. (If self-indicating – check the colour of the tell-tales).
Query column. Has it been properly stored (out of sunlight with column ends capped)? How did it perform last time it was used?
Dismantle the inlet. Inspect the liner and any surfaces/seals at the bottom of the inlet as debris can accumulate here. Replace liner and (gold) seal if necessary (depending upon manufacturers instructions).
Replace the septum (ensure you have the correct septum for your application in terms of bleed profile and inlet temperature).
Inspect the inlet liner and check for cleanliness. If in doubt replace the liner with a freshly deactivated new version – check that the liner geometry/packing is appropriate for your method.
Replace nuts and ferrules on each end of the column.
Cut the ends of the column and inspect to make sure the cut is straight and there are no rough edges (be especially careful here as the quality of the cut can determine peak shape and quantitative reproducibility).
Note your manufacturers recommended insertion distance (inlet and detector) on the column and move the nut to ensure correct distance at each end (pushing a septum onto the column prior to the column nut and ferrule can help to keep the nut at each end at the correct height whilst installing the column).
Insert the column into the inlet. Tighten the ferrule and gently pull the column to check if the fitting is tight enough. Grip the column and continue to tighten about 1/8 turn until the column can't be moved.
Switch on the carrier gas and verify that a pressure/flow is present.
Input column dimensions, carrier gas, and whether constant flow/constant pressure is to be used into the instrument.
Switch on the inlet and detector heaters, and the detector gas flows.
Leave the column at ambient temperature and purge dissolved oxygen from the phase for 10 – 15 mins.
Set the oven to the condition temperature and leave for 1 hour. (10 °C above the maximum oven temperature of your method or at the gradient upper temperature limit of the column – whichever is lower).
Cool the oven and then run at least 1 full temperature program according to your analytical method.
Perform a test injection to check method performance.