Gas Chromatograph(y) or GC
Split/splitless, SPS, or whatever you refer to it as has been around for decades. One of the most common inlets to be found on any GC today, this single part can be attributed to a majority of the issues found with a GC and methodology.
In past newsletters, I’ve spoken about the usefulness of vapor volume calculators and how they go relatively unused as a method-building tool. Using this tool will help avoid <25% of GC service calls that I have seen. Other inlet-related issues can be troubleshot with the below advice.
First, and foremost, I always start with “what was the last thing done to the GC?” This is a surprisingly effective way of zeroing in on the root cause of many issues. After I try to find out “what hasn’t been done?” This will often bring about lapses in maintenance and other good housekeeping practices related to GC.
Note: Assuming flows and temperatures are not an issue.
Maintenance is often overlooked as a root cause of instrument issues. When was the needle/septum/o-ring/liner/gold seal/split filter changed? When was the last time anyone flushed or changed the split vent line (on applicable GC models)? If the answer to these questions is a mystery or spotty at best, then it’s always good practice to perform thorough maintenance and try running some blanks and a sample to see if the issues persist.
Outside of this, there can be leaks from any sealing point that need to be addressed. If a leak detector is not available, mix 1:1 H2O:IPA which will create a viscous enough liquid that will create bubbles from a leak when applied by a pipette. DO NOT use “Snoop” as it will contaminate your system and require parts to be replaced.
If there are any questions concerning further troubleshooting, I am always available to assist!