By Kaf on Friday, March 30, 2001 - 01:59 am:
Where do I can find the relation between the optimum pH and the best ion pairing at this pH ?
By Uwe Neue on Friday, March 30, 2001 - 03:24 pm:
The typical ion-pairing reagents are long-chain sulfonic acids or long-chain quarternary amines. They all work the same way, and they are (nearly) independent of the pH. The optimum pH may be more a function of your analyte(s) than of your ion-pairing reagent.
By Brian on Monday, April 9, 2001 - 05:06 pm:
I would suggest that the pH should be 2 units below the pKa if the analyte is a base or two units above if it is an acid. For carboxylic acids, this is pH 6-7 and for bases usually < pH 7, which is the highest most columns will take. So chances are pH 6 will work for whatever you've got.
Usually, I start at 5 mM with the cheapest ion pairing agent I can find (Tetrabutylammonium sulfate for acids, sodium hexanesulfonate for bases).
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