gc help needed

[martinamarie]

Hi, I am working on a method transfer for residual solvents (ethanol and ethyl acetate)
The method uses a purged packed inlet and an innowax megabore column and headspace.

I am unable to get the chromatography of the 1st lab. My peaks are running at 50 % of their retention time. In addition, they appear to have 2 solvent peaks (dmf) where as I have 1 peak
I cannot tell what is wrong.

Does anyone have any ideas

Thanks

MartinaMarie

[Peter Apps]

First guess is that the film thickness in your column is half what it is in theirs, this is presuming that you have accurately duplicated all the other conditions.

What is a "purged packed inlet" ?

Peter

[GasMan]

Peter,

It is a packed inlet with septum purge.

Gasman

[larkl]

Are the flows and temperatures the same?

[Peter Apps]

Thanks GasMan - is there packing in the inlet or is it an inlet for a packed column ?.

MatinaMarie

Do you have pressure rulation or mass flow regulation on your GC ?, and how are you measuring the actual gas flow through the column ?

Please post the full details of the instrument set up in both labs, then we have all the information in front of us right from the start.

Thanks Peter

[GasMan]

Peter,

For Agilent/HP it is a standard packed inlet, either with EPC or manual pneumatics.

Gasman

[martinamarie]

Hi, thanks for the replies its EPC controlled.