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Leuprorelin - Amino acids
Posted: Mon Dec 06, 2004 4:35 am
by dontibr
Hi friends I am analysing Leuprorelin - identification of amino acids analysis [As per EP] but as per EP, the method needs 3 pumps, so I selected Dabsyl chloride method. Can any one please suggest me the HPLC method for amino acids after Dabsyl chloride reaction. and also please mention the concentrations [ Sample and standard- if any experience with this material ] - I got method with Novogram column through net searching but it is not that much good.
Thanks in advance
Posted: Tue Dec 07, 2004 12:00 am
by Uwe Neue
I do not know if you have consider the AccQ-Tag method. It is very fast, very sensitive, and the amino acid separations have been worked out already. Check on the Waters website for information on the method, if you are interested!
Posted: Tue Dec 07, 2004 4:11 am
by dontibr
Hi,Uwe Neue thanks for the reply, I will try for that method
AA determination
Posted: Thu Dec 09, 2004 2:32 pm
by Benjamin
Dear Dontibr,
If I understand well your problem, you want to determine some amino acids present in your product, which I assume is a peptide of sorts.
The AcuTag method Iam sure it will work well, but you can also use well documented and openly available procedures that do not require expensive reagents, special columns, and even the purchase of ready-made mobile phases (such as Waters AcuTag method).
Why dont you try FMOC derivatization? This procedure is simple, the reagent is inexpensive, the reactions are fast, and the derivatives are stable (1 day or so).
Any reference book on Derivatizations, will give you the initial conditions to employ.
Also, perhaps you should consult with Agilent about their AminoQuant method.
Good Luck,
Benjamin
Posted: Mon Dec 20, 2004 11:59 pm
by dontibr
Hi thanks to all for the replies, Finally I got good metod with Dabsyl chlorination and reproducability is good.
Posted: Tue Dec 21, 2004 9:22 am
by kiknos
congratulations!
may we get to share your great experiences?
thanks,
kiknos
Posted: Tue Dec 21, 2004 10:07 pm
by Einar Ponten
Goochh..
Having this hydrophilic and UV absorbing compound, HILIC would have been a "one pump route" without derivatization.
Simple is beauty!
Posted: Mon Dec 27, 2004 11:49 pm
by dontibr
Hi Kiknos, With in a week I will post the extraction method and Analysis method of Amino acids.
Hi Brahmareddy
Posted: Tue Dec 28, 2004 11:12 am
by Ramasarma
Hi how ru?
When u r coming to india? check the waters website u can get the method
bye for now
Posted: Wed Jan 05, 2005 2:06 pm
by HW Mueller
dontibr,
I have great admiration for anybody getting anything useful with dabsyl derivatization. Actually, I did not have so much a problem with precision, but rather with accuracy. Do you have any indication of your accuracy, and if so, how do you know?
Benjamin,
do you have any details on the deterioration of Fmo-derivatives? One can buy all kinds of Fmo-derivatized amino acids, so under proper treatment these are indefinatly stable. Also I don´t recall any decomposition problems with Fmo-baclofen (a synthetic agonist of GABA), but then I didn´t look for it.