Weak cation-exchanger

Weak cation exchanger—macroreticular type—carboxylic acid or phenolic functionality... 

A weak cation-exchange resin is obtained by reaction of glyoxylic acid and a cross-linked polyvinyl alcohol. The polyvinyl alcohol is cross-linked with glutaraldehyde in the presence of hydrochloric acid. The cation-exchange resin has an exchange capacity of 3 meq/g or greater and a swelling volume of 10 ml/g or smaller (37-38). 

Xu, W. and Regnier, EE., /. Chromatogr. A, Protein-protein interactions on weak-cation-exchange sorbent surfaces during chromatographic separations, /. Chromatogr. A, 828, 357, 1998. 

II Weak cation-exchangers are not available based on silica. Why not (refer to Fig. 3.3a). 

Ion chromatography using a weak cation-exchange column with direct conductivity detection was applied in the determination of aqueous tributyltin ions, with short elution times LOD 0.01 ppm, without preconcentration or derivatization. No organotin remains adsorbed on the column94. 

Fig. 20. Test of stability of weak cation exchange monolithic column (ISCO). Conditions column, 50 X4.6 mm i.d., mobile phase gradient of sodium chloride in 0.01 mol/1 sodium phosphate buffer (pH 7.6) from 0.1 to 0.5 mol/1 in 4.5 min and to 1 mol/1 in 6.5 min, overall gradient time 11 min, flow rate 10 ml/min. Peaks Ribonuclease (1), cytochrome c (2), lysozyme (3). The two separations shown in this figure were achieved 503 runs apart...

Weak cation exchange resins (carboxylic acid type) have been widely employed for the isolation and detection of marine PSP s. However, the less basic gonyautoxins (GTX s) tended to elute with the solvent front with these resins — especially when very crude... 

Polymethacrylate Weak cation exchanger (carboxylic acid) ProSwift WCX Dionex Corporation 50x4.6mm 50x 1 mm Ion exchange chromatography of proteins... 

In addition to classical reverse phase separation of peptides on octadecyl derivatized silica monoliths, sugars and peptides as well as proteins and nucleosides have been analyzed on a 20-cm-long silica-based poly(acrylic acid) column (ID. 200 pm), employing HILIC and weak cation-exchange chromatography, respectively [194]. Furthermore, HILIC fractionation of polysaccharides delivered remarkable and promising results [84,194]. 

In the original parfait system, the silica gel created problems by acting as a weak cation exchanger and by leaching silicic acid to the anion-exchange bed and into the final effluent. These silicate residues interfered with the recovery of compounds from these sources. 

Determination of cations is one of the most important analyses for the routine quality control of fruit juices and purees. Weak cation exchangers are in general highly selective with respect to the H+ ion ... 

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