Isoelectric buffers, part 3: Determination of pKa and pI values of diamino sulfate carrier ampholytes by indirect UV-detection capillary electrophoresis
✍ Scribed by Sanjiv Lalwani; Edward Tutu; Gyula Vigh
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 151 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0173-0835
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Ampholytes with close p__K__~a~ values (i.e., good carrier ampholytes (CAs)) are needed as buffers in pH‐biased isoelectric trapping (IET) separations. The syntheses of two families of such good CAs were reported recently. Members of the family of diamino sulfate ampholytes (first series) had p__I__ values in the 5.7 < p__I__ < 9.0 range. Members of the family of quaternary ammonium dicarboxylic acid ampholytes (second series) had p__I__ values in the p__I__ < 4.3 range. To further characterize the diamino sulfate ampholytes, their effective mobilities were measured by indirect UV‐absorbance detection capillary electrophoresis in a series of background electrolytes (BGEs) with different pH values. The p__K__~a~ and limiting ionic mobility values of the CAs were obtained by fitting these mobility values, as a function of the pH and the ionic strength of the BGEs, to the theoretical mobility expression. These diamino sulfates complete the list of CAs suitable for IET separations.