Chromatography Forum

Tests either in hplc or in gc needed. is there any method for testing dma hcl (N-methylmethamine) by gc or hplc???


please help.

I would recommend cation exchange chromatograph (IC) with conductivity detection.

See a typical column out of the Metrohm range: Metrosep C 4 - 140/4.0
Eluent conditions: 1.7 mmol/L nitric acid, 0.15 mmol/L dipicolinic acid, 3% acetonitrile (0.9 mL/min).

Fastest way is probably GC - I seem to recall some even sell "amine" columns.

Thanks for all for the reply.
I think there is a misunderstanding in my words.

I will clarify.
I am asking about DIMETHYLAMINE HYDROCHLORIDE
All the suggestions above are for DMA.

I am asking about DIMETHYLAMINE HYDROCHLORIDE
All the suggestions above are for DMA.

In aqueous solution, they are the same thing: dimethylammonium ion.

Thanks for the clarification.

Is there any method using ODS column (C-18) or a cationic SCX column???
Bcoz i have these both columns in hand. Can i test using these columns???

If it is there, please explain me the method.

The scx column (cation exchange) might work.
Us an acidic eluent with some organic modifier with a conductivity detector.
The dimethylammonium cation is retained on the cation exchanger material and will be eluted mainly by the H+ of the eluent acid. The organic modifier speeds up the separation and improves the peakshape.

Hello Vishnu.
Use GC wich Fid ; packing column (5% Carbowax+ 1% KOH * on S1), head space (90 C) wich water solution or extract on CHCL3 + one drop of NH3 solution.
inj - 100c det -150C , column 60->120 5 C/min.

You detremine [url]dimethylamine as base[/url] and calculate by hydrochloride.

Ion chromatography (HPLC) admixting iones in drug substancies in a salt forms - is a big problem...

Is UV visible detector effective for that in HPLC???
At what nm i can use for DMA???

you cannot use UV for this compound, despite the fact that some people think. Your choices for this are LC/MS, ELSD, RI, conductivity and nitrogen detector. if you want to see both ions 9amine and chloride) you need trimodal column like Obelisc N or Obelisc R. If you are looking only at amine you can use Primsep mixed-mode column, similar to this:
http://www.sielc.com/Compound-Ethylamine.html

you can use your SCX column in the same fashion with ELSD, RI or conductivity

Dimethylamine do'n have chromoforic groups (double bonds).
You can (should) use a admixting of chromofors (benzene , nafthalene and any dues) in liquide phase and register negative peaks in UV-DAD , but this LC- method is'n effective, selective and robatic.

I say. Dear Vishnu "do not torture yourself and chemin de fer " - use a valid GC method by packing column...

I would recommend cation exchange chromatograph (IC) with conductivity detection.

See a typical column out of the Metrohm range: Metrosep C 4 - 140/4.0
Eluent conditions: 1.7 mmol/L nitric acid, 0.15 mmol/L dipicolinic acid, 3% acetonitrile (0.9 mL/min).

your Ca and Mg peaks are miss identified. They should be reversed, with Ca eluting before Mg.


http://www.metrohmusa.com/Products/Ion- ... Cbr+%2F%3E

Tests either in hplc or in gc needed. is there any method for testing dma hcl (N-methylmethamine) by gc or hplc???
please help.

I think the most important question hasn't been asked yet . WHAT kind of test do you exactly need?
Verifying identity? Assay? Purity? Anything else?
Nevertheless I'd say my choice would be GC...

Oops, just realized that this thread is more than a year old ...