Strange area pattern in MHE-GC

[michael78]

Hi all
I am setting up a MHE method with 4 injections on an Agilent HS sampler (model 4557) for a residual solvent method (ethanol, toluene and acetone in API).
My areas for the ethanol peak does not behave as expected: The first peak is low, the second and third peak are higher than the first peak and have same size, and the fourth peak is lower than the first. The method I use has previously been working well on a Perkin Elmer HS sampler.

Please suggest way to improve the method on the Agilent HS sampler.

Cheers,
M

[LiVD]

It sounds like your autosampler is not going through the pressurize-depressurize cycle it needs to go through for MHE.

[kubowicz.tomasz]

Hello

What you have is poor reproducibility. Possible reasons:
-leak in HS sampler (sample loop, pressurization valve, vent valve).
-leak in GC (transfer line-inlet tubing, septa, vent trap/tubing, valves or EPC module)
What you need to do is to find a leak.

Regards

Tomasz Kubowicz