aminoacids

[Norma]

Hullo I want to know if somebody have experienced the analysis of aminoacids with ion pairing.

[DSP007]

Hullo I want to know if somebody have experienced the analysis of aminoacids with ion pairing.

Yes! More detail is impossible to say. Because the issue is set incorrectly, some amino acids ? matrix ? concentation?

[Norma]

More details :Proline in honey at concentration of 500 ppm.

[Norma]

Excuse me for yhe smile , its proline in honey.

[DSP007]

Well. Bitten.
"Bite me bee"

I got out of the wide leg ...
E Heftman Chromatography fundamentatals & Applications of chromatograpic & electroforetic metod.Amsterdame-Oxford-NY 1982, translate ChD A V Rodionov PHD V G Berezkin M1986
17) -Bohlen P, MelletM Anal Biochem 94 313 1979
Proline/oxiproline DC-4A citrate buffer Pftalac aldehyde derivates fluorimetry
Sensivity- 10 picMol proline per ml urine.
Dealing with honey is realy better than in the urine.

IMHO better HPLC wich dancil derivates after flash chromatography on strong cation

PS
http://de.wikipedia.org/wiki/Honig
read book 9 Helmut Horn, Cord Lüllmann: Das große Honigbuch, Kosmos, Stuttgart 3. Aufl. 2006 - 1200 p-p . Germans are very well suited to checking the literature, and 'there is a lot to dig'.
http://elibrary.ru/item.asp?id=6576581
Food Manufacting referative Index , Honey , manufacting ,aminoacid

http://www.sciencedirect.com/science?_o ... archtype=a

[Norma]

Thanks for the replay. Actually I want to know if somebody knows if there is any method without derivatization for aminoacids

[lmh]

done it once, worked beautifully, but I will never ever do it again. I used an LC-MS and was seeing little but nonafluorpentanoic acid for 2 months.

[HW Mueller]

I have done hydroxyproline and fluoroproline with HILIC and UV detection. The high concentrations I needed made this a bit difficult (appears that overloading was playing into this).

[DSP007]

http://en.wikipedia.org/wiki/Proline

Proline not have chromophore groups and you will not see it optical UV detector with sufficient sensitivity.
Only use LC-MS , if "don't derivate"

You are not alone
http://www.chemport.ru/forum/viewtopic.php?f=12&t=62079

[mairz]

Hi

I don't know if I should post a separate thread for this (moderator please advise), but for now I'll post my question here:

I have been using and OPA method for the analysis of 24 amino acids and biogenic amines using an Agilent 1100 with automated pre-column derivatisation. The method works perfectly well, has been validated and published, but, but but....I really do need to measure Proline and have decided to try the Waters UPLC Accuity method.

Now, we have a UPLC with both fluorescence and UV detection, I have the C18 BEH column, but the Waters people here in France tell me that I will need to purchase a kit to the tune of 5000 € in order to obtain the results they publish in the application note. Also, the composition of the mobile phases included in the kit are 'confidential' and apparently the instrument needs to be reconfigured which can only be done using the CD supplied with the kit.

So, before making this investment, I was wondering if anyone out there with any experience of this could offer some advice or pointers.

Thanks

[Mattias]

http://en.wikipedia.org/wiki/Proline

Proline not have chromophore groups and you will not see it optical UV detector with sufficient sensitivity.
Only use LC-MS , if "don't derivate"

You are not alone
http://www.chemport.ru/forum/viewtopic.php?f=12&t=62079

The carboxylic acid group has a good absorbance at 200 nm. I have a LC/UV method for methionine using a Primesep 100 column and a mobile phase of water/H3PO4/ACN that works perfectly at 200 nm. The samples I analyse contain 1000 ppm methionine, and the peak is almost too high for the detector (1 AU).

Unless the interferences are killing, this approach should work also for proline in honey. Just keep the mobile phase free from UV-absorbing stuff.

[DSP007]

The carboxylic acid group has a good absorbance at 200 nm. I have a LC/UV method for methionine using a Primesep 100 column and a mobile phase of water/H3PO4/ACN that works perfectly at 200 nm. The samples I analyse contain 1000 ppm methionine, and the peak is almost too high for the detector (1 AU).

Unless the interferences are killing, this approach should work also for proline in honey. Just keep the mobile phase free from UV-absorbing stuff.

Hello
Yes of couse. But I think,is not the best way honey, too much substances absorption at 200 nm. That is, frontal attack does not guarantee success. It is better still to go through sorption to HCX (or in SAX - as acid ) and derivatization. As they say (song) "normal (in the sense non-Crazy) heroes always go around ".

As the flood.
Matthias is not as frequent name in Denmark. Do you happen to have been in Moscow in 2008 ?

[Mattias]

Never been to Russia!

One good thing about running cation-exchange (Primesep 100) is that you can run with a lot of acetonitrile in the mobile phase. It has no impact on the retention of the amino acid. In a way you are doing SCX-cleanup already on the column since all hydrophobic (neutral and anionic) junk elutes in the front. It could actually work.

One more thing, many of the molecules that have retention on SCX (SPE or LC-column) will react during an amine derivatisation, since they often contain amines. That would give a lot of peaks anyway, maybe not so different from using no derivatisation?

This is just speculations of course, but could be worth a test.

[Norma]

Matias can you tell me the pH of your mobile phase? Thanks

[Mattias]

Matias can you tell me the pH of your mobile phase? Thanks

The pH is not so important, it is the ion strength that elutes the amino acids from the SCX column.

I have used the following conditions for methionine on Primesep 100:

Mobile phase: mix 500 ml of water and 500 ml acetonitrile. Add 2.5 g of phosphoric acid.
Column: Primesep 100 (3.2*150 mm)
Temp: Ambient
Flow: 1 ml/min (isocratic)
Retention time methionine: 4.5 min