Chromatography Forum

Greeting,

I would like to know if it is OK to use NMP as a solvent for RP-HPLC analysis with 5uL injection.

Is it going to ruin the C18 stationary phase? I do observe a huge peak at void.

thanks

and what about DMA?

Thanks

I wish I knew what “NMPâ€

For starters, I have no idea if you can use either solvent in RP-HPLC. My guess is probably "it depends". More info on either solvent...

Google tells me NMP is N-Methylpyrrolidone, and DMA is Dimethylacetamide.

NMP "is the lactam of 4-methylaminobutyric acid and a very weak base. NMP is a chemically stable and powerful polar solvent. These characteristics are highly useful in a variety of chemical reactions where an inert medium is of concern. Despite the stability of NMP, it can also play an active role in certain reactions: hydrolysis, oxidation, condensation, conversion with chlorinating agents, polymerization and o-alkylation, and related reactions."

http://www2.basf.us/diols/bcdiolsnmp.html


DMA is "used as a solvent for polyacrylonitrile, vinyl resins, cellulose derivatives, styrenes and linear polyesters. Also used as a catalyst and solvent in elimination, halogenation, cyclization, alkylation, interesterification, and phthaloylation reactions."

http://www2.dupont.com/Products/en_RU/D ... de_en.html


I assume more info from moonchips may be necessary (for the smart guys on the forum):

Column type? Perhaps manufacturer, packing material, length, I.D., etc?

Other mobile phase constituents?

pH?

Temperature?

Detector?

Analyte type/names?


I found one aplication note for a "N-Methylpyrrolidone (NMP) + 0.1M LiBr mobile phase" in the analysis of 'Poly (Vinylidene Fluoride)' on 'Jordi DVB GBR Mixed Bed Linear' column, 500 x 10mm ID

http://www.gentechscientific.com/an59.htm


I found an abstract more a method using DMA as a constituent of a mobile phase on a C8 column "for the sample preparation and handling for the determination of amino acids, monoamines and metabolites from microdissected brain regions of the rat".

http://www.medscape.com/medline/abstract/9698226


Mostly, though, it seems these solvents are used in SEC/GPC.

"I would like to know if it is OK to use NMP as a solvent for RP-HPLC analysis with 5uL injection." - by the things you write I'm guessing you wanna use it as a diluent

The size of the injection does say nothing without size of the column

Taken all into account I personally wouldn't worry about the column

"I do observe a huge peak at void. " - you do inject polar solvent right?

What about dissolving your analytes in these solvents, and then diluting with some other solvent like MeOH/ACN/Water or simmilar to get rid of the huge peak at void?

Moonchips,

Do you want to use it as diluent for your samples or in the mobile phase?

It has quite a high UV cutoff so detection by UV might not be the most practical choice ( http://macro.lsu.edu/HowTo/solvents/UV%20Cutoff.htm).

I wouldn't see any problem in injecting it in any HPLC column or using it as
mobile phase till you can stay under the maximum tolerated column pressure and have a decent detector.


Do you plan to use it for non aqueous RP?
http://macro.lsu.edu/howto/solvents/Pol ... 0index.htm


Regards,
bhuvfe

Sorry for any confuse.

NMP is N-Methylpyrrolidone, and DMA is Dimethylacetamide.

I would like to use them as sample diluent and inject directly onto HPLC.
Column: YMC C18, 100*4.6*5
Temperature: 25
Mobile A: 0.05% TFA
Mobile B: 0.05% ACN
PH: 2
Detection: 240nm UV
analyte: small API with MW about 500 base molecule
injection size: 5uL


Thanks a lot

I would agree with grzesiek then, such a small amount of solvent shouldn't be an issue as an injection solvent. However, I do wonder why you aren't just dissolving your standards/samples in your mobile phase?

DMAC and NMP help with solubilizing samples in a smiliar fashion to DMSO without the added viscosity.

With silica based C-18 columns like yours they have not caused me any problems in the past and I have seen their use in the literature.

Ah, I see. I'm not a pharma guy, so I learned something today. Yippee!