Chromatography Forum

Dear All,

I have come back to GC after ten years of absence.
We have PerkinElmer AutoSystemXL GC, column HP-5, FID detector.
Well, since we have a lot of rutine analysis we change liner every 4 days. Liner is PE Split/Splitless Liner 2mm x 4.0 x 86.2. We fill it with glass woll. Injection volume of sample is cca. 0.2 microliters. Solvent methanol.
Yesterday after routine change new liner filled with glass wool solvent peak inceased in size and exibits long tail. Previously very good seaparated peaks (R>2.5) are nov sitting on a long tail from methanol peak.

Thank you. D.

Swap the liner again, and while doing so check that there are no fragments of ferrule or septum in the bottom of the inlet body.

With such a small injection volume I presume that you are doing split-splitles injections ? If so, check that the split really does open at the specified time.

Check that the injection volume has not changed.

Inspect the first meter or so of the column for disrupted stationary phase, bits of septum or glass wool, or ferrule fragments. If it looks dodgy, cut the end off the column.

Peter

Huracan,

I may be confusing posts.... From what you describe I would suspect either of two things. First, I would suspect a splitter valve not turning on to sweep the inlet. You should hear the valve click on. Second, and more likely considering the described symptoms, I would be suspicious of too much wool. It is rare but I have seen liners packed with so much wool that you don't actually get good vaporization but rather a long slow vaporization.

Best regards,

AICMM