Chromatography Forum

Porapack R and Porapack Q column - What is the phase of these columns?
I am having trouble while using Porapack R for Residual Solvent IPA
The column shows decreasing peak response after longer use and RT also get changed.
How to tackle this Problem.
Ple help me out.

The R and Q polymers are not a phase, but are different receipes of porous plastic having different co-polymers with divinylbenzene.

If you inject non-volatiles on the packing it can become blocked and the eluting solvent peaks can become distorted and have different retention times.

Molecules of chain length of less than 7 carbons are analyzed with these packings.

Without more information these is not much more I can add.

best wishes,

Rod

Thank Rod,
I am using Porapack R for Inprocess Reaction Monitoring analysis for IPA in Milled Granules. The Sample prep is 1gm diluted to 100 ml with methanol.
These granules have Excipients also.
Std prep 3 ml IPA diluted to 200 ml of it 2 ml again diluted to 200ml with same Methanol.

Porapak R and Q are both divinylbenzene porous polymers.
difference is surface area. The Q has much more retention and loadability, meaning you have to run it at higher temperature to get the components off. The Q is used most of the time.
If retention is changing it can be many things. Assuming that the flow is the same, and you see lower response, the column may get contaminated, blocking the pores. May use the for higher capacity, inject less or use a bit more sample cleanup. Also you may consider to use a liner with some glasswool, so you can replace that section periodically.

Thanks Rod
It was really a best suggestion.
I did the exact same as u mentioned.
It worked!
till now the analysis ids going smoothly
Thank u very much.

Porapak R and Q are both divinylbenzene porous polymers.
difference is surface area. The Q has much more retention and loadability, meaning you have to run it at higher temperature to get the components off. The Q is used most of the time.
If retention is changing it can be many things. Assuming that the flow is the same, and you see lower response, the column may get contaminated, blocking the pores. May use the for higher capacity, inject less or use a bit more sample cleanup. Also you may consider to use a liner with some glasswool, so you can replace that section periodically.