[analytical.484]

Hello,

I am currently developing a residual solvent analysis method by Gas chromatography equipped with a flame ionization detector. My sample is an API with a phosphate salt attached. One of the residual solvents of interest is triethylamine. When my sample is spiked with the residual solvents, all other solvents show recovery except for triethylamine with a recovery of ~75 %. I think it is because of the triethylamine reacting with the phosphate salt in the sample. I have tried adding a base such as NaOH to remove the phosphate salt from the sample first, then adding the triethylamine, but the recovery is still not showing. The sampler used is the headspace sampler and the diluent is NMP.

Please let me know if you have any advice on how to make the recovery better.

Thank you.

[rjb]

Hi OP,

Your base addition makes a lot of sense, but I wonder if there is something going on within instrument; possibly activity in the liner or maybe column...
Can you give us some more details of your process, run parameters (i.e. injection, programme) and setup (i.e. Column type, liner type) please?
As an aside, have you been able to get a decent result from TEA alone at all?

Kind Regards

R

[analytical.484]

Thank you for your reply!

These are the current parameters and setup:
- headspace sampling
- inlet temp: 210 deg
- detector temp: 230 deg
- oven program: 120 deg for 15 min, then 50 deg/min to 220 deg for 5 min
- sample volume: 1 mL
- column: HP-1 (60m x 0.53mm, 5um)
- liner type: split liner
- split ratio: 5:1

Please let me know if there's any other information you would like to know!
Thank you

[MOTOBALL]

As an aside, have you been able to get a decent result from TEA alone at all?

This is a critical piece of information that is required to properly diagnose your problem!!!

Regards,

Motoball