Help please with an analysis

[Tristan]

Hi all!!

I need help with a HPLC analysis. I want to analyse iminobis(methyl phosphonic acid) and can't find any information, or know where to start. Does anyone have previous experience with this, or could point me in the right direction as a good starting place?

Thanks all in advance!!

[laserman]

I do not know what kind of detector you have.
I hope this application will help you.
http://www.sielc.com/application_203.html

Best Regards,

[mohan_2008]

From laserman's application:

Typically, you need an ELSD detector. I do not know if this molecule has a UV absorbing chromophore, inorder to use a UV detection.

Start at low pH with the following conditions:

Column: Zorbax SB C8 or equivalent
Mobile phase: 50% ACN & 50% H2O and 0.1% TFA (gives pH = ~2.0)
Diluent: check solubility in the mobile phase or use an appropriate solvent.
Injection volume: 10 uL (to start with)
Column Temp: 60 C (from laserman's application note)
Auto sampler Temp: 23 C (I hope this product is thermally stable)

Detector: Use a PDA/DAD detector and obtain a spectral scan, 190 -400nm. Derive the best wavelength channel for your assay. Use this channel for your data acquisition for maximum accuracy.

Once you have your detector wavelength, optimize the other variables as needed.

[Uwe Neue]

I have serious doubts that a reversed-phase column will do anything for such a polar compound. Either ion-exchange as suggested by laserman, or HILIC would do. There is no useful UV, so the first thing is to think about what detectors you have available.

[mohan_2008]

It apparently seems so.

But, I would give it a try playing with the HPLC variables and obtain a better k value.

If I can manage to get a peak atleast around 3 minutes, that should be great.

However, I completely agree that it is a pretty polar compound and may have to be worked out with either an Ion pair or Hilic technique.

[Vlad Orlovsky]

This molecule has no UV activity and will not retain on C8 or C18 column without ion-pairing reagent (basic IP).

You need to use ELSD, CAD or LC/MS. On our website we have similar applications, just go to applications by compound and look for glyphosate intermediates and alendronic, ethidronic acids (cannot post link as chromforum server gives me "forbidden" message. You need to go to mixed-mode ion-exchange, ion-exchange or HILIC for this compound

P.S. Even opening new account did not help with "forbidden" message