Chromatography Forum

Hello All

I want to analyse the mixture of ethanol, water and higher amines (boiling point 365 0C). I have gone through many catalogue but not found the best column.

Kindly suggest me.

Thanx
Nisha

Hi
Well, packed colmns you may think .... for example 5% OV-17 on diatoms, soaked in 2% KOH.

However, we say in Russia "dung fly [must be] separately from the meatballs. " Better to make two or three different methods. It is possible that the water in the mixture easier to determine the Fisher and amines - HPLC or TLC.

Hi Nisha

What do you want to detemine ?; the amines, the ethanol. the water. all three at the same time ? Only telling us the boiling points of the amines does not help much, what compounds are they ?.

Peter

Hi
Well, packed colmns you may think .... for example 5% OV-17 on diatoms, soaked in 2% KOH.

However, we say in Russia "dung fly separately from the meatballs. " Better to make two or three different methods. It is possible that the water in the mixture easier to determine the Fisher and amines - HPLC or TLC.

Thanx

Hi Nisha

What do you want to detemine ?; the amines, the ethanol. the water. all three at the same time ? Only telling us the boiling points of the amines does not help much, what compounds are they ?.

Peter

Thanx
Ya, all three at the same time. amine is trioctyl amine.

Hi Nisha

I'll stick my neck out here and say that there is no column that can sensibly handle all three compounds, and no detector that will practically see all three.

So you need three methods - Karl Fischer for the water, equlibrium headspace with a wax type polyethylene glycol column for the ethanol, and a base-deactivated polar column for the amine. If the matrix is mostly ethanol then you could probably just inject product.

All of this is hugely dependent on the concentrations of the three components.

Peter

Hi Peter, Nisha,

Water and ethanol can be done my many porous polymer columns, A or N or R would be my preference.

TOA can be done by many column, preferable a capillary;

or a packed column Supelcoport coated with 3-10% Apielzon L with 2% KOH

Water will tail unless it is in small amounts.

All three analytes can be seen by HID or DID or TCD detector. TCD is the cheapest and the easiest.

I would try a FS coated SS tube and inject directly onto column to a TCD. You will have to program temp the column oven to get the elution of TOA in a timely manner.

DO NOT USE ANY SILICONE PHASE WITH KOH. I repeat: DO NOT. Sorry DSP007, but your advice is not good. The KOH will quickly destroy the silicone phase, even OV-17. Bleed Bleed Bleed will result.

best wishes to all,

Rodney George