Optimization of a multi-elemental preconcentration procedure for the monitoring survey of dissolved metal species in natural waters

The monitoring of dissolved metal species in natural waters is pursued through the development, optimization and verification of a multi-elemental extraction procedure based on the cloud point phenomenon. More specifically, six metal species were extracted from water samples as their pyrrolidinedithiocarbamate complexes and subsequently isolated from the aqueous matrix in the micelles of a non-ionic surfactant upon increase of the solution temperature. The optimum experimental conditions that ensure the efficiency of the procedure have been investigated and are presented in detail. As an analytical demonstration, the method was applied to the monitoring survey of two natural ecosystems in Northwestern Greece in an annual monitoring study. The measured concentrations of dissolved metal species were deployed to estimate the pollution status of the ecosystems and unravel the mechanisms that contribute to the metal load.