Transition Metal Analysis with Spectrophotometric Detection

Transition Metal Analysis with Spectrophotometric Detection 

According to Fig. 4-48, both cation and anion exchange processes contribute to the separation of transition metals with complexing agents in the mobile phase. Hence, before the introduction of ion ejodiangers with defined anion and cation 

The introduction of the lonPac CS5 separator column [28] in the mid-1980s finally remedied the problems associated with the determination of iron(III). The CS5 column is a latexed anion exchanger with mixed anion and cation 

A reversal of the elution order for metals such as lead, cobalt, zinc, and nickel is obtained with the use of oxalic acid as a single complexing agent. Under these chromatographic conditions, the metal separation is controlled by anion and cation exchange processes. The degree to which each mechanism contributes to the separation process depends on the stability of the oxalate complexes (see Table 4-5) and is, therefore, different for each metal ion. The anion exchange 

The best ion chromatographic method for the simultaneous analysis of chro-mium(III) and chromium(VI) at present is based - according to Somerset [37] — on the ion-exchange separation of both species with post-chromatographic oxidation of chromium(III) to chromium(VI), which can then be detected photometrically at 365 nm. The oxidation is carried out with potassium peroxodisul-fate, using silver nitrate as a catalyst. Complete conversion is achieved within a short time by raising the reaction temperature to 80 °C. 

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Transition Metal Analysis with Spectrophotometric Detection... 

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