The development of an analytical method for the study of the distribution of metal-complexes in aqueous slurries of sediments

Abstract

A method has been developed to study the distribution of Cu-EDTA and Pb-EDTA complexes in aqueous slurries of sediment. This method involves separation of the metal-EDTA complexex by ion-exchange chromatography on a reversed-phase C 18 column coated with Cetrimide (ion-pair reagent) followed by UV-detection measurement at 258 nm. The chromatographic method provided good separation of Cu-EDTA from Pb-EDTA within 15 min. The new method was tested with a sediment slurry spiked with Cu 2+ and/or Pb 2+ , and EDTA. For this purpose, a micro-extraction cell was added prior to the analytical column to allow the direct injection into the HPLC of whole slurries (suspended sediment in contact with metal ions and EDTA). Preliminary results showed that the time-dependent distribution of Cu-EDTA or Pb-EDTA in contact with sediment can be followed. The detection limits for the Cu-EDTA and Pb-EDTA sediment slurry were 1.32 nM and 2.03 nM, respectively.