Chromatography Forum

First-time user of this forum, so apologies if this topic has been addressed previously.

Does anyone have an efficient method for washing SDS out of a C18 column ? Either your own recipe, a literature reference or general reading suggestions would be appreciated.

Thanks,

JMB

I do this all the time. It takes a wash first with 90% methanol for 3 column volumes followed by acetone for 3 volumes at 1 mL/min. The first removes the SDS, the second removes the SDS impurities.

Mark,

Thanks for your input.

JMB

Dear JMB,

Was the Mark's suggestion efficient?

Have godd elutions!!!

Carlos Teixeira

Carlos,

I requested this for an off-site collaborator and forwarded the info. to him; he was away from his lab. last week, so I'm hoping for some good news this week.

I'll post the outcome here.

Thanks,

JMB

As alternative which does not require the removal of ion-pairing reagent or equilibration of IP you might want to consider Primesep columns were ion-pairing reagent is attached to the surface of silica. Columns retain compounds based on reverse phase and ion-exchange mechanisms (dual or mixed mode interactions):

http://allsep.com/Technology_RetentionO ... pounds.php

http://allsep.com/Newsletters_Home.php

Regards

I'm hoping for some good news this week.

JMB, have any good news?

I do this all the time. It takes a wash first with 90% methanol for 3 column volumes followed by acetone for 3 volumes at 1 mL/min.

Mr Mark, is acetone (100% as suggested) compatible with materials (PEEK tube, seal) in the LC system?

Regards

For brief exposure and low pressure, PEEK and piston seal materials are compatible with acetone. Normally I flush the column and pump briefly with methanol after the acetone so that the equipment is not left standing full of acetone.

Vlad,

Enough already, we have all read from you 100 times now that Allsep makes mix mode columns. They are great, send you a sample you will develop a method for us. Please, enough.

Tom

Tom,

What is wrong with developing methods for people in need? Is it wise from the business point/ end user that a chemist with average pay of $30/ hour spends days and days developing method. People ask particular method and we are willing to develop it for free and fast. Find another company which will use this approach. We developed few methods for people from this board and I don't see them compalining. Our messages are addressed to people who need help and our help is practical, not like "go try this..it did not work, now go try this...

P.S. By the way Allsep is ion-exchange column from Vydac and has nothing to do with us.

Sorry for being cranky. I know you mean well and for all I know you provide excellent customer service. I know you are with Primesep, my Alzheimer's was flaring up. Your commercial just doesn't need to make it into every thread. The poster asked about removing SDS from a C18. I appologize to all for letting my crankiness contaminate this thread.

Accepted. I know that a lot of times I am getting close to the border line but I mean good intend. It is killing me to see people not using new tools, doing the same thing over and over again, getting frustrated, puzzled and discouraged. I spend 10 years in major pharma company and only now I know what efficiency is. Efficiency is money, product and projects delivered in time and may be at the end cheaper drugs (Am I delusional or what?)
Our system with switching valves and column switchers allows us to do method development very efficient. I just spend only a few hours developing the method for serine, GABA and methionine (from another thread). The reason we are asking for samples is that sometimes they are expensive and not readily available plus people like to see exact application. In addition to that we like challenges and each application when people don't know what to do is a good motivation to take this challenge.

My apologize to people who are annoyed by my posts, I just want to help (may be not just help)

Regards,

Vlad

SIELC_Tech, I think you just give us an alternative for IP chromatography. I appreciate it.
In my case, I did not mean to use SLS in IP chromatography (as the content of the mobile phase) but when it is as sample solvent, especially in dissolution medium - Maybe different with JMB's question.
May there be a possibility that a portion SLS from the sample solution is bound by stationary phase and need to be cleaned by strong solvent?

syx,

"May there be a possibility that a portion SLS from the sample solution is bound by stationary phase and need to be cleaned by strong solvent?"

The answer to your question is: yes, in most cases unless your mobile phase has quite a bit of solvent in it you can expect that SLS will concentrate on the C18 phase but as to whether or not this will effect subsequent chromatography significantly, this depends upon the SLS concentration in your sample. Elution with a high solvent content mobile phase is efficient and quantitative.

try 70%organic solvent alongwith 40'c column oven during washing for 1hr