[STM]

Hello everyone. Please I need your advice.

I am presently doing HPLC separation of lipid hydroperoxides via UV detection at 234 nm.

I have successfully separated the lipid hydroperoxide on HPLC using  Acetonitrile: 0.1 % Acetic acid (90:10) as eluent. The RT was 4.3 and it was highly reproducible.

My concern is that acetonitrile is expensive. Hence, I am thinking of replacing it with Methanol in the same ratio. However, I am concerned that methanol and acetic acid may react.

Will methanol and acetic acid react even in the absence of sulphuric acid as required in typical esterification reactions. Will it be safe to proceed with this mixture as HPLC eluent?

Thank you

[Arkcon]

No methanol and acetic acid are compatible as mobile phase.  Its done all the time.

You may get different specificity with methanol vs ACN, you will simply have to try and see.

Now methanol is slightly less nonpolar than ACN.  For the 90% concentration you're at, this is a non-issue, but the usual hint is to increase the concentration by 10 % when substituting methanol for ACN.  Maybe you'll need to make your mobile phase 0.1 % acetic in 100% methanol?  That won't react either, its been used before.

I'm guessing you're using a typical reverse phase HPLC column in all of my hints.  More info would allow more people to help.

[STM]

@Arkcon:

Thank you for your response.

Yes, I am working with a RP-HPLC system. I will post my new observation when I have the results.

Thank you

[STM]

Dear Arkcon,

Thank you for your response. I have been able apply the methanol:acetic acid solution as HPLC Eluent and it worked.

Thans for the advice.