New stationary phases for efficient separations and selectivity studies in anion chromatography

摘要

Spacer arm anion-exchange resins for single-column ion chromatography (SCIC) were prepared by a two-step procedure consisting of a bromoalkylation of Rohm \u26 Haas XAD-1 resin under mild conditions, followed by amination with trimethylamine. The five resins prepared are all of a similar, low capacity and contain a one-, two-, three-, four- or six-carbon spacer arm linkage between the resin surface and the quaternary ammonium exchange group. The selectivity of these resins for mono- and divalent anions is evaluated and explained using classical ion-exchange theory. Separations are presented to demonstrate resin selectivity and to show the usefulness of these resins for practical ion chromatography;Trimethylammonium, tributylammonium and tributylphosphonium anion-exchange resins were synthesized and used for SCIC. The three resins were prepared using a 7 to 12 [mu]m polystyrene-divinylbenzene resin and are all of a similar, low capacity. The selectivity of these resins for mono- and divalent anions is examined and related to classical theory. It is shown that the unique selectivity obtained with the quaternary phosphonium resin is of practical value in the separation of anions;A new stationary phase for anion chromatography was prepared by a simple method of coating quaternized latex particles onto the surface of unsulfonated polymeric resins. A nonporous polystyrene resin of very uniform particle size is described that serves as an excellent substrate for the coated resins. These latex-coated resins are used to obtain highly efficient anion separations.