Glyphoste & Glufosinate

[Davidantony]

Dear All
We have in process of developing a method for glyphoste & glufosinate in waters quottro micro LCMSMS.In most of the method it determined by derivitisation by FMOC-Cl using sodium tetra borate as buffer.But it is not derivatized properly because we dont get the proper mass on tuning.Please sugest a proper method to find thease compounds

[James_Ball]

Here is a method where they are looking for Glyphosate and AMPA underivitised which should also work for the Glufosinate.

http://cdn.intechweb.org/pdfs/15724.pdf

It is using an extraction (for soybeans) with water/dichloromethane then cleanup of the aqueous with methanol to remove the proteins, followed by dilution and injection. The mobile phase is Water and Methanol with Ammonium Carbonate.

[chemex]

I am in the early stages of the development of a method for the detection of Glyphosate and AMPA. I am derivatising with FmocCl and the borate buffer as well and it is working although I still need to find the LOD.

I used:
spiked water sample
Sodium thiosulfate solution
Borate buffer pH around 9
FmocCl solution

Reaction overnight at room temperature in the dark.

SPE extraction the very next morning.

I am able to identify Glyphosate (168, 390) and AMPA (110, 332) with a SIM method in the negative mode.

[Camisotro]

One could also use a HILIC strategy to retain glyphosate and then detect it without derivatization.

[yangz00g]

Glyphosate is difficult for LC-MS without derivatization.

[Camisotro]

Glyphosate is difficult for LC-MS without derivatization.

In initial tests, it seems to be doable on our system using a HILIC strategy without derivatization. I haven't come back to this further yet, though, as the client who requested it has yet to send samples.

[emelteker]

hello
ı tried hılıc column by lcsmsms for glyphoste, but ı can not see signal Can you see with hılıc column glyphosate.can you help me?

[Camisotro]

hello
ı tried hılıc column by lcsmsms for glyphoste, but ı can not see signal Can you see with hılıc column glyphosate.can you help me?

Which HILIC column? We're using a zwitterionic column and Gly retained very strongly. So strongly that:
- I first had to use flow injection (no column) to find the MS signal for Gly. It can be seen in both positive and negative mode but on our instrument positive was better.
- Next I found that it retained completely at high levels of organic modifier, and I had to reduce down to the 10-30% ACN range in order to actually get the damn thing to elute off the column.
- Normally methanol is not a suggested HILIC solvent as it provides a lot less retention than ACN, but in this case it was beneficial because we needed more elution.
- The peak tails horribly because there is so much affinity for the column. This was the case when the aqueous phase had 5 mM ammonium formate, or 10 mM ammonium acetate, or 0.1% formic acid. However with A=0.5% formic acid (normally a bit high for LC-MS) and B=methanol, I was able to reduce tailing to an acceptable level at ~30%B.

One possibility might be to get a very short HILIC column (guard column even?), as the affinity for Gly is so strong that you'll actually get better results with less column.

[emelteker]

thank you for your help.
Did you try eurl srm method ver 7 for glyphosate ? ı trıed method 1.1 for glyphosate by waters quatro prımıer xe lcmsms. But ı could not obtained succesful results with this metod. after this study, we didn't observe signal in MS Dedector, so this metot is very problematic.
ı have waters Beh hılıc cloumn.ı think this column is not succesful.because zwitterinc and beh hılıc cloumn are not same particul. is it true?
ı am considering to try eurl srm method ver 7 1.3 for glyphosate.
For glyphosete, would you share your experience ?
Thanks

[Camisotro]

BTW it appears you are using a Turkish keybord layout to enter English, which results in the dotless "ı" appearing sometimes when you mean to type "I" or "i".

No I have not tried an SRM. It looks like that method uses very harsh conditions with a type of column we don't presently own. We bought our HILIC column to do melamine and cyanuric acid, so glyphosate was just something I tested on it to see if it would also be viable on the same column.

You are suggesting the problem is your column, but you also say you observed no signal in the MS detector. You probably will want to split those problems apart. Your first diagnostic should be to take the column out completely and do infusion or flow injection to see the glyphosate MS signal. Once you know exactly what it looks like on your detector, and you optimize the masses and energies needed for MS/MS, you can work on the chromatography next.

[emelteker]

hii
we already tuned infussion of glyphosate and While tuninig glyphosate we can see MS values of it.our problem is after injection we cant see peak.

[Camisotro]

hii
we already tuned infussion of glyphosate and While tuninig glyphosate we can see MS values of it.our problem is after injection we cant see peak.

OK. Next, what kind of HILIC column were you injecting it on and what is your mobile phase? You're not giving me much to work with here.