Elution with Perchloric Acid and Sodium Perchlorate

1 Elution with Perchloric Acid and Sodium Perchlorate 

The approach is to measure retention times of metal cations on columns containing low-capacity resins with eluents containing perchloric acid or various perchlorate salt.s. The perchlorate anion is used to eliminate any possible complexing of a metal ion by the eluent anion. Retention factors (k) are calculated from the retention data. 

Eluents containing hydrogen ions or sodium ions were used at concentrations ranging from 0.10 to 1.0 M. In general, narrow chromatographic peaks were obtained, although the rare earth peaks were broad with some tailing. 

The retention factors were calculated from the retention times and are given in Tables 5.4 and 5.5. The data show that, as expected, eluents containing sodium(l) are more efficient than those containing hydrogen(l). The data in these tables are arranged in order of increasing capacity factors. In this way it is possible to compare the relative affinities of the various divalent and trivalent metal ions for resin sites. 

Note that there are crossovers in the retention factors of lead(ll) and several trivalent metal ions as the eluent concentration is increased. 

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