Chromatography Forum

I need to analysis methylparaben in gel product by HPLC
I tried to extract methylparaben from gel by methanol, dissolved gel by methanol, the stored at -20 C, centrifuged at 15,800 RPM for 30. I would not get rid off the gel .
Does anybody have experience to precipitate gel? thanks.

We assay gel samples frequently here, usually blend with organic solvent, then filter through HPLC sample membrane filters.

If you heat/stir to dissolve, it will likely re-gel.

There is an opportunity to do direct injection of gelatin matrix samples with either:

Cadenza HS-C18 (hydrophopic / hydrophillic hybrid ODS)
http://www.imtaktusa.com/site_media/fil ... TI387E.pdf

OR

Presto FF-C18 (2um non-porous C18):
http://www.imtaktusa.com/site_media/fil ... TI567E.pdf
.

depending upon the product excipients, you may be better off simply extracting in MeOH over a steam bath...

Thanks everyone. It really help!!!!!!!
Jady

Jady I'm curious, which way worked for you?

Hi everybody
Please help...
I am new here and completely freshly new in HPLC.
My expertise is formulation, not so much analytical techniques
My problem is similar to Jadys.
I have some drugs (poorly water solubles, like indomethacin) in gelatin and I should analyze them by HPLC.
So how exactly to get rid of the gelatin? I taught of precipitating and filtering it. But which solvent to use?
And at which temperature to heat?
I have this column : LiChrospher® 60 RP-select (5 µm)
Could I use it, since I am not sure we could buy new one, like Bryan suggested: Cadenza HS-C18 (hydrophopic / hydrophillic hybrid ODS) ?

Thank you all for help

Blend with solvent that your active is soluble in. Filter. Simple is usually best.

Hey, I'm having a similar issue. Developing method for CHG related compounds in a gel product. The problem is I need to dilute the gel 50% to get the correct concentrations I'm looking for. I need to be able to inject a preparation that has 2mg/ml.
I don't have much experience in sample prep development beyond dilution in diluent, etc.
The gel is extremely viscous, so when mixing 50:50 with diluent....not all that much happens.
Any suggestions for how I should go about this?

Sorry to hijack the thread, but same problem I guess.

Hey, I'm having a similar issue. Sorry to hijack the thread, but same problem I guess.

We assay gel samples frequently here, usually blend with organic solvent, then filter through HPLC sample membrane filters. If you heat/stir to dissolve, it will likely re-gel.

What I posted above. Twice.

yea, that's not working..

yea, that's not working..

Then it's time to hit the bench and earn your keep !!!

haha, I'm hittin the computer to do the Reseach part of my job, just exhausting all possibilities before I hit the bench

when mixing 50:50 with diluent....not all that much happens.

And FYI ^^^ As you can see from my first post I already tried what you suggested. Twice.

Have you tried freezing the sample then pulverizing?

Have you tried different solvents and mixtures?