Cation exchanger latex-agglomerated

Fig. 1. Simultaneous separation and detection of anions and cations on a latex agglomerate column. Column Dionex HPIC-CS5 cation exchange column (250X2 mm) with precolumn HPIC-CG5 (50 X 4 mm) eluent 0.5 mM copper sulfate, pH 5. 62 flow rate 0.5 ml/min sample volume 20 gl containing 0.1 m M of each ion detection two potentiomet-ric detectors equipped with different ion-selective electrodes in series. Peaks (1) chloroacetate, (2) chloride, (3) nitrite, (4) benzoate, (5) cyanate, (6) bromide, (7) nitrate, (8) sodium, (9) ammonium, (10) potassium, (11) rubidium, (12) cesium, (13) thallium. Reprinted with permission from [10].

Like anion exchangers, cation exchangers are divided into polymer-based cation exchangers (PS-DVB, EVB-DVB, polymethacrylate, and polyvinyl copolymers), latex-agglomerated cation exchangers, silica-based, and other (e.g., crown ether, aluminia materials).Modern cation exchangers contain sulfonic, carboxylic, car-boxylic-phosphonic, and carboxylic-phosphonic-crown ether functional groups. 

Latex cation exchangers were introduced by Dionex Corp. 10 years later than latex-agglomerated anion exchangers. These types of cation exchangers consist of a weakly sulfonated PS-DVB substrate with latex beads with a very small diameter agglomerated on its surface by both electrostatic and van der Waals interactions. 

Armed with several anion-exchange columns and an eluent solution of 2.0 mM KHP (pH 5.0), Siriraks et al. set out to determine why the elution order they observed (Zn-Pb-Cu) was different than that reported by Jenke and Pagenkopf [20]. They studied the chromatographic behavior of Pb(II), Zn(II), and Cu(II) on four different anion-exchange columns in an attempt to elucidate the mechanism of retention for the three cations. The following columns were used in the study silica-bonded from Vydac (302.IC) polystyrene-divinylbenzene (PS-DVB) from Hamilton (PRPX-100) pol)miethacrylate from Waters (IC-Pak) and a latex agglomerated PS-DVB from Dionex (AS-4). 

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