Fast copper speciation screenings with solid-phase extraction cartridges using high-specific activity 64 Cu

Abstract

Solid-phase extraction (SPE) cartridges with different functional groups(chelating, ion-exchange, hydrophobic) may be useful for copper speciationdeterminations of aqueous samples. Provided that each cartridge selectivelyextracts one species or a group of species, a fast screening of copper speciationcan be achieved by performing a series of extractions with different SPE cartridgesand combining the results. For this purpose, the performance of five SPE cartridgeswas studied with respect to extraction selectivity using samples with knowncomposition. Samples were spiked with a high-specific 64 Cu radiotracer toachieve easy detection of extracted copper species. Its high radioactivityper unit of mass ensures preservation of initial chemical equilibria and compositionof the sample. Results show that secondary interactions may take place onthe extracting phase when relatively clean samples are analyzed. Two naturalwater samples, viz. a ditch water and a seawater sample, were exposed to aseries of extractions as well. Species distributions found for these samplesgenerally correspond to expected distributions. Secondary interactions maybe suppressed in these cases, as other metal species compete for these interactions.