Opinion on THF

[mfpmg]

Hello.

I've asked some quotations for THF HPLC grade.
One company advised me that THF HPLC grade costs around 300-600€ (a bottle of 250 mL) and that there are some companies that sell THF for protein reactions as HPLC grade for about 30€/L.

I'm just wondering if anyone ever had this dilemma? I mean, I don't want to buy THF of worse quality/not suitable for what I want to do, but I also don't want to buy 1L of it for 1200€, as I'm going to use it frequently.

Thank you very much for your input.

[scottythree]

For what it is worth this link is Sigma Aldrich current pricing (US):

http://www.sigmaaldrich.com/catalog/pro ... &region=US

[Perreman]

Well this type of questions are always tricky. HPLC grade can vary quite a lot depending on manufacturer and batch variations, but in the end all that matters is if it's good enough for your specific application. I'd suggest buying a small quantity (perhaps the salesmen can give you a freebie?) from two or three different manufacturers and try them out with your application.

[Gerhard Kratz]

Check out also Carlo Erba and Scharlab. I would recommend to distill the THF before use and keep it in a UV light protected brown bottle and make aluminium folio around the bottle. A UV spectrum check of your THF is always recommended. Good luck.

[mfpmg]

For what it is worth this link is Sigma Aldrich current pricing (US):

http://www.sigmaaldrich.com/catalog/pro ... &region=US

Well this type of questions are always tricky. HPLC grade can vary quite a lot depending on manufacturer and batch variations, but in the end all that matters is if it's good enough for your specific application. I'd suggest buying a small quantity (perhaps the salesmen can give you a freebie?) from two or three different manufacturers and try them out with your application.

Check out also Carlo Erba and Scharlab. I would recommend to distill the THF before use and keep it in a UV light protected brown bottle and make aluminium folio around the bottle. A UV spectrum check of your THF is always recommended. Good luck

Thank you, scottythree
Thank you, Perreman
Thank you, Gerhard Kratz

The thing is, I've already asked quotations to other companies and they sent me prices in the range of 30-50€/L for THF HPLC-grade. For instances, the price for 2,5 L of THF for HPLC - not stabilized from Carlo Erba was ~40€.
This was the only salesman that told me that there are some companies that sell THF for protein reactions as THF HPLC-grade, and that the "real" THF for HPLC costs around 300€/250 mL. This would imply that the other companies are losing on profit (because they could charge ~100 times more for this product), which I seriously doubt.
Futhermore, if I never talked to this salesman, I would probably buy the cheaper option. However, I read that THF causes degradation of the columns and seals, and I'm afraid that using one that's not for HPLC (or so he says) could accelerate that process.

[Rndirk]

Futhermore, if I never talked to this salesman, I would probably buy the cheaper option. However, I read that THF causes degradation of the columns and seals, and I'm afraid that using one that's not for HPLC (or so he says) could accelerate that process.

I haven't used THF for HPLC. But it's also what I've heard. If it's the THF itself that can damage tubings and stuff, then a higher or lower grade will not matter for that purpose. See this discussion.

Out of curiosity, is there a reason why you need to use THF?

[mfpmg]

Futhermore, if I never talked to this salesman, I would probably buy the cheaper option. However, I read that THF causes degradation of the columns and seals, and I'm afraid that using one that's not for HPLC (or so he says) could accelerate that process.

I haven't used THF for HPLC. But it's also what I've heard. If it's the THF itself that can damage tubings and stuff, then a higher or lower grade will not matter for that purpose. See this discussion.

Out of curiosity, is there a reason why you need to use THF?

Thank you for the page you've sent.

THF (5%), together with water, methanol and acetonitrile, will be the mobile phase in a protocol that aims to evaluate methylparaben, propylparaben and phenoxyethanol in a cosmetic sample.

[Consumer Products Guy]

THF (5%), together with water, methanol and acetonitrile, will be the mobile phase in a protocol that aims to evaluate methylparaben, propylparaben and phenoxyethanol in a cosmetic sample.

Yes, about 20 years ago we found methyl paraben and phenoxyethanol to elute close to each other on RP-18 columns, especially if the column had been in use some time already. I liked THF in the mobile phase to affect better separations (even though I can't say I fully understand its actions).

We actually used a specialty intrinsically-deactivated column for this assay back then to make things easier, was called a Prism RP; I have no idea if such column is still available, but would sometimes actually reverse the elution order, stuff like that, was really helpful for sometimes difficult separations, like triclosan from triclocarban, which otherwise would require THF.

Remember to buy THF without UV-absorbing preservatives, so buy in small containers.

[mfpmg]

THF (5%), together with water, methanol and acetonitrile, will be the mobile phase in a protocol that aims to evaluate methylparaben, propylparaben and phenoxyethanol in a cosmetic sample.

Yes, about 20 years ago we found methyl paraben and phenoxyethanol to elute close to each other on RP-18 columns, especially if the column had been in use some time already. I liked THF in the mobile phase to affect better separations (even though I can't say I fully understand its actions).

We actually used a specialty intrinsically-deactivated column for this assay back then to make things easier, was called a Prism RP; I have no idea if such column is still available, but would sometimes actually reverse the elution order, stuff like that, was really helpful for sometimes difficult separations, like triclosan from triclocarban, which otherwise would require THF.

Remember to buy THF without UV-absorbing preservatives, so buy in small containers.

Thank you very much for your intel!

I've never done this experiment before and the protocol is new to me, so if I have any difficulties I'm going to check on those columns.

[tom jupille]

As far as I know, Prism columns are still available from Thermo.

[DR]

Kratz got most of what I'd have said - except... Nitrogen blanket those 1L bottles EVERY time you use them, and don't forget the peroxide test strips, safety people love & swear by those things.

[mfpmg]

Katz got most of what I'd have said - except... Nitrogen blanket those 1L bottles EVERY time you use them, and don't forget the peroxide test strips, safety people love & swear by those things.

Thanks, DR.
The thing is, we have a relatively small lab and actually most of the equipment I'm going to use to perform the analysis was ordered last week (including volumetric flasks and pipettes and such), so I'm not going to have the possibility to nitrogen blanket the bottle, at least for now. Do you have any alternative to that?

[Consumer Products Guy]

Katz got most of what I'd have said - except... Nitrogen blanket those 1L bottles EVERY time you use them, and don't forget the peroxide test strips, safety people love & swear by those things.

Thanks, DR.
The thing is, we have a relatively small lab and actually most of the equipment I'm going to use to perform the analysis was ordered last week (including volumetric flasks and pipettes and such), so I'm not going to have the possibility to nitrogen blanket the bottle, at least for now. Do you have any alternative to that?

We used 1 liter bottles of THF so they wouldn't hang around long after opening/use.

If you have GCs around, perhaps you have some helium for keeping air away after use.