Analysis of chromium(III)-fluoride-complexes by ion chromatography

A method for the ion chromatographic separation of cationic CrF(x)-species in aqueous acidic solutions with photometric detection is described. CrF(3)-, CrF(+)(2)- and CrF(2+)-species can be separated on a commercial cation-exchange column using HCl/2,3-diaminopropionic acid (DAP) as eluent. The chromium(III)-complexes are converted with 2,6- pyridinedicarboxylic acid (PDCA) into the violet Cr(PDCA)(2)](-)-complex at temperatures >90 degrees C by post-column derivatisation for the subsequent spectrophotometric detection at lambda=335 nm. Iron- and nickel-ions do not disturb the determination even in concentrations higher than those of the chromium (III)-ions.