Een ionchromatografische methode voor de bepaling van chroom(III) en chroom(IV) in drink-, grond-, regen-, en oppervlaktewater in het lage picomolbereik

An automated ionchromatographic method for the simultaneous determination of low contents of trivalent and hexavalent chromium in water was developed and optimised for the valence-specific analysis of chromium in different types of water. The speciation was carried out on a mixed anion and cation exchange column of Dionex type XS5A. High sensitivity was achieved using a preconcentration of a 6 ml sample with two CG5A guard columns and a post-column reaction based on the catalytic oxidation of luminol and chemiluminescence detection. The detection limit of chromium(VI) described with the ionchromatographic system in Milli Q water is 20 ng/l (100 pmol/l). For chromium(III) the detection limit was 6 and 90 ng/l (200 and 600 pmol/l), respectively. The resolution between chromium(III) and chromium(VI) is excellent with R>10. Application of the method was tested for drinking water, rain water, groundwater and surface water. The analysis time of the chromium components is less than 30 min. The operational parameters for the method are described in an useful format