Fixing coelution issues?

[TheBupKing]

We continually get issues with one of our analytes having a coelution with matrix peaks in SIM mode on one of the qualifying peaks. Using a Agilent 6890 with a restek column. I am trying to learn as many fixes as possible to this issue, since we encounter it quite frequently, especially as the column is shortened over time. I have had some success with reducing temperature and carrier gas flow rate. I have also tried cold trapping the analytes at the start of the run, which works intermittently.

I am a bit of a newbie when it comes to more complex troubleshooting and method optimization with the GC, so please bear with me.

[chromatographer1]

you seem on track. More plates = better separation = longer column or different column = cooler oven or sharper inj plug

do what you can money + wasted time are trade-offs

Rod

[TheBupKing]

you seem on track. More plates = better separation = longer column or different column = cooler oven or sharper inj plug

do what you can money + wasted time are trade-offs

Rod

That would be the goal, to create better separations without changing columns. Not only does it cost money to get columns, it also costs money to have the instrument down for 2-3 hours. Would like to learn of other techniques/parameters to play with.

[fsistere]

Can you change the qualifiying peak? Are there another ion that haven't this interference?

[TheBupKing]

Don't know. It's a long established method, and we don't have coelution all the time. As we get towards the end of the column life, we start to see it and would like to find ways to extend column life.