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TFA for Ion pairing
Posted: Mon Oct 18, 2010 3:52 pm
by MestizoJoe
Does anyone know the best TFA concentration to use for ion pairing? I know the column can only adsorb so much. Using a concentration higher than that which will cause max adsorption is useless, but I don't know the concentration. It's probably dependant on organic concentration, too.
Thanks,
Posted: Mon Oct 18, 2010 4:20 pm
by SIELC_Tech
The impact of TFA as ion-pairing reagent for analysis of small molecules is overrated. What kind of analytes you are trying to analyze?
Posted: Mon Oct 18, 2010 9:01 pm
by MestizoJoe
I'm sort of asking what the rating is.
I know I can use other IPR's but unfortunately I don't have time for that.
Posted: Mon Oct 18, 2010 9:25 pm
by SIELC_Tech
The rating is 1
Concentration of TFA depends on your analyte and column. You need to make sure that your column can tolerate low pH (2 and below). I would start with 0.1% TFA
Posted: Tue Oct 19, 2010 5:55 pm
by MestizoJoe
I am guessing going above 0.1% won't help much. I looked at Practical Method Development by Snyder and he has some really nice graphs showing retention vs ion pairing reagent concentration but nothing for TFA. Probably because it's better used as a modifier. Oh well haha.
Posted: Tue Oct 19, 2010 6:08 pm
by SIELC_Tech
That is because TFA is not very good IP, try something else:
http://www.tciamerica.com/useful-info/p ... A1084E.pdf
alternatively you can use Primesep column with IP reagent embedded on the surface of silica gel:
http://www.sielc.com/pdf/SIELC_June_2004.pdf (in these applications TFA is not ion-pairing reagent but source of ions facilitating ion-exchange mechanism)
http://www.sielc.com/pdf/SIELC_June_2009.pdf
We never used IP in our lab, for us IP is dead