Cation exchange columns Hamilton

Water-methanol (1 1) extraction As(III) and AB separated on cation-exchange column (Hamilton PRP-X200) in pyridine formate 4mmolL pH 2.8 As(V),... 

Many different experimental systems for analysis of amino acids have been described, but the most successful from the standpoint of high-resolution analysis of physiological fluids is the system described by Hamilton in which he was able to separate at least 175 components in human urine (H3) using a single cation exchange column system. This... 

The surface-sulfonated cation-exchange columns from Wescan are packed with 10 pm spherical resins with an exchange capacity of 0.1 mequiv/g. The Hamilton PRP X 200 resin has a similar capacity (0.035 mequiv/g) and is available in 3 pm, 10 pm and 12-20 pm particle size. 

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). 

The Dionex column caused each of the metal ions to be completely retained. The authors reasoned that this behavior was due to the presence of unreacted surface-sulfonated PS-DVB macroparticles which were capable of adsorbing the metal cations. A mixed retention mechanism was theorized for the other three columns. In addition to anion-exchange of negatively charged metal-phthalate complexes, the authors suggest that adsorption of neutral metal-phthalate complexes might contribute to the retention of each metal ion. This theory was based on the fact that since the stationary phase of the Hamilton, Waters, and Vydac columns were comprised of different materials, these materials would have different hydrophobicity which would lead to differences in adsorption of the neutral metal-phthalate complexes on each column. This was corroborated experimentally, as the metal ions were retained more strongly on the more hydrophobic column (PS-DVB from Hamilton). The dominant mechanism of retention was similar for each column because there were no differences in metal ion elution orders between the three columns. 

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