This change in elution order is a beautiful example of the control ofselectivity that ion pairing reagentscontribute to the tool-kit of the methods development chemist.Dorothy PhillipsWalter Foster
Aqueous–organic mobile phases with ion-pairing reagents should contain also a buffer with the pH adjusted to enhance the ionization of weak acids (higher pH) or bases (lower pH) to obtain adequate retention. The retention in IPC can be controlled by changing the type or the concentration of...
Typical Ion-Pairing Reagents: For anions: ammonium and tetramethyl-, tetraethyl-, tetrapropyl-, and tetrabutyl-ammonium hydroxides. For cations: hydrochloric, perchloric, and perfluorocarboxylic acids;pentane-, hexande-, heptane-, and octanesulfonic acids. ...
Another factor influencing the formation and retention on the stationary phase of the ion pairs is pH. Many analytes and pairing reagents are weak acids and bases. For example, compounds such asalkanesulfonic acidsor quaternaryammonium compoundsare typically used as modifiers. Therefore, in the solut...
Additional insight into the ion pairing process can be gained by considering the temperature-dependence of the association. Using our polarisable model, we have determined the variation in the ion pairing free energy over the range from 290 to 350 K (Supplementary Fig.19). From a linear fit...
Complete resolution of the 12 peptides was achieved via a novel CE approach: a capillary zone electrophoresis (CZE) mode effected a separation of identically charged peptides; within each charged group of peptides, the addition of perfluorinated acid anionic ion-pairing reagents allowed resolution ...
challenge of using water as a solvent usually encompasses the reaction of immiscible reagents55,56,57. In the hydroformylation of long-chain alkenes this two-phase extraction technique is not appropriate, given their poor solubility in the aqueous catalyst phase and thereby limited mass transfer and...
The effect of different concentrations of triethylammonium or tetrabutylammonium salts as ion-pairing reagents, as we... S Eriksson,G Glad,P? Pernemalm,... - 《Journal of Chromatography》 被引量: 122发表: 1986年 Chiral resolution of aminoalcohols by ion-pair chromatography Chiral resolution of ...
Methods for chromium with use of triphenylmethane reagents are less sensitive; examples are: Chrome Azurol S (ε = 5.9·104) [43,44], Xylenol Orange (ε = 1.0·104) [45], and Malachite Green [46]. A much higher sensitivity is obtained when Cr(III) is determined with the use of Erio...
This work describes a comprehensive characterization of the factors controlling the floatability of free gold from flotation test using reagents (collectors) at plant concentration levels. A relationship between the collectors loadings on gold particles and their surface composition has been established. Th...