Chromatography Forum

Hello,
I have been trying to separate the impurities in the API with GC-FID using a glass column, packed with 3% G-16 phase. I could able to separate all the impurities except one inmpurity which is not base line resolved. The impuriy comes right after analyte but was not baseline resolved. I moved from 3 mm ID X 2 meter column to 2mm ID X 3 meters columns but still no improvement.

Can you please suggest me possible other trials that I could separate?

What are the USP specification for the impurity separation? I mean Resolution.

Best Regards,
kish

you might try a capillary column in a megabore 0.53mm ID dimension with 1 to 3 micron film and a flow rate of 10-15 cc/min in your packed column instrument to get more separation.

Rodney George

"What are the USP specification for the impurity separation? I mean Resolution. " - what are your clients needs?

"The impuriy comes right after analyte but was not baseline resolved. " - so how much is it resolved?

Hello,
Ther R=1.6 but not baseline separated. Like a vally peak.To validate the method (ICH) we need baseline separation.

Thanks,

"To validate the method (ICH) we need baseline separation. " - who says that?

Is the impurity needs to be baseline separated for validation of analytical method?

Regards

It is interesting that going to a 3m from a 2m and from 3mm ID to 2mm ID did not make any difference. I suspect the longer column was poorly packed.

You also might try changing the phase loading on the support, or choose a different support, Chrom P-NAW instead of Chrom W-HP.

If you can describe the analytes involved (paraffin and olefin, for example) I might suggest another column and modification of the packing.

You can email privately if you do not wish to discuss the problem publicly.

best wishes,

Rodney George
consultant

"Is the impurity needs to be baseline separated for validation of analytical method? " there is no such obligation as far as I know