Analysis of metals

The AMGC (Analytical, Environmental and Geochemical) Department of VUB focuses on assessing the concentrations of inorganic contaminants, i.e. the metals and their speciation but also aims at the measurement of tracers of water masses and suspended matter. With the passive samplers of the DGT type (Diffusive Gradients in Thin Films), only labile pollutant fractions, hence the most toxic and ecologically relevant, will be measured. The passive samplers show a high capacity and allow the quantification of ultra-low pollutant concentrations, down to levels that are impossible to attain through spot sampling. This approach has the advantage of avoiding matrix effects and allows estimation of contamination levels in a large water mass, smoothing out small-scale variations. When DGT samplers were retrieval from the field, resin gels were peeled off and eluted with 1M HNO3 and at the end were analysed by HR-ICPMS (Thermo element 2).  The amounts of metals accumulated by the DGT (mass metal/mass resin) can be expressed in classic concentration units (molar or mass metal/volume seawater) via the characteristics of the sampler and the deployment time.  In order to compare the passive sampling, seawater samples are also taken directly from the sampling sites and were followed by field filtration with 0.45µm Durapore filters, acidification by HNO3 and analysis by HR-ICPMS, which gives the concept of total dissolved metal concentrations.  In laboratory, suspended matters on the filters were dried and digested using Aqua Regia for metal analysis.