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- Posts: 52
- Joined: Fri Sep 30, 2011 2:24 pm
Problem is that every so often the run fails rsd of nmt 4%. Get rsd's usually around 10% from three injections.
I have tried changing everything before a run (septum, liner, oring, ferrules). I only take one injection per vial. Usually the last injection jumps up to an area of ten but it can be random. It's only the rsd of toluene that's important. Retention time is around 6.2min. Also
I have checked for leaks and pretty sure it's fine.
Db5 column
GC 6890.
Carrier gas: helium (7ml/min), splitless.
Inlet temp: 245C
Detector temp:300C
Purge on 1min @ 25ml/min
Program: initial 35C for 8min; 15C/min to 290C, Hold 25min.
0.5ul from 5ul needle.
Injector speed fast.
Liner straight, tapered bottom.
Any tips would be helpful. Please don't ask me to change any parameters above as this method does not allow. Except purge time which can be 1 to 1.5min.