ION PAIR Reagent

[oscarBAL]

Hello All,
I am trying to find a char or nomogram about IP reagent selection.

I remember I saw it once in the internet, but now I can't not find'it.
It is not the first time that I dont't have a spesific reagent a y loose many time trying to figure out what other reagent I can use...

Thanks in Advance.

Oscar.

[Uwe Neue]

There is a table in Journal of Chromatography A Volume 499, 19 January 1990, Pages 423-434 that covers this - atleast for every second ion-pair reagent.

[juddc]

Excellent reference - thanks.

I'm currently working on optimizing an IP separation for a particularly complex sample and it's been a while since I last worked with IP agents to any real extent, so this is most timely. My work has been roughly parallel to this, but it's largely been from memory.

BTW, I've tried HILIC a number of different ways (amino, Luna HILIC), a polar embedded phase RP, and a mixed mode column. On all of them I was able to retain my compound of interest but was not successful in getting a clean chromatogram from a sample. SPE didn't help either, so I pulled out the rack of IP agents and viola, I had enough flexibility to really control selectivity the way I need to.

IP can be a pain and it has its limitations, but it certainly has its place and shouldn't be forgotten. It sometimes works when nothing else does!

[Einar Ponten]

May I ask? Did you ever consider why your selectivty options were limited with silica and amino columns?

I am confident that the zwitterionic stationary phase (ZIC®-HILIC) can provide you with the necessary freedom in mobile phase pH and buffer ion-strength that you apparently need.

Please give us some more information about your compound. After all, chemical problems need such information...

[juddc]

Hi Einar,

It's not the analyte I had a problem with moving around - I was able to get it to retain on three completely different column chemistries; it's other largely unknown compounds in the complex and largely unknown sample matrix that were making things difficult. It's hard to be confident that any single column or separation scheme will work when you only have good information on what you're looking for and (comparitively) very little information on what it's in.

Amino, silica, and the mixed mode column are what I have in my inventory currently, the chemistry I'm dealing with will covalently modify certain moities which rule entire classes of separation media and mobile phase components out, and I don't want to buy a column before I've exhausted possibilities with my current tool set. Also, I can't get into the precise details of my project in a public forum.

I'm certain there are a number of ways to get the job done and I've already found quite a nice one with IP. Old fashioned isn't bad if it works for the problem at hand.

I'm not looking for help or advice as I have thnigs well in hand; I was merely thanking Uwe for putting the citation up.