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IPMA complete metal analysis in seawater samples
UNICA (University of Cagliari) organized a conference the 20 June 2019 in Cagliari
Data Quality Assurance: a holistic view
DGT Conference 2019 will be the fifth international scientific event with MONITOOL presence in 2019
MONITOOL partners share results and plan next steps in Gran Canaria
Technical conferences present MONITOOL project and DGT passive sampling in Canary Islands
Interview with Thi Bolam, leader of MONITOOL Work Package 5
ITC will organize 2 technical conferences in the days preceding the next partners´ meeting in Canary Islands
UNICA promotes the application of the MONITOOL approach for other organic compounds
DCU analyses biofouling on MONITOOL DGTs
Organisation of the interlaboratory DGT exercise by IFREMER, October 2018
Database Management and correlation studies. First promising results.
Interview with Dr. Blánaid White, coordinator of Interreg founded MONITOOL project
MONITOOL partners discuss project´s first results in AZTI, San Sebastián
AZTI hosts 3rd MONITOOL meeting in San Sebastian
DGT extraction and metal analysis by IFREMER
Determination of lead and cadmium labile fraction by Anodic Stripping Voltammetry and total dissolved Nickel Cathodic Stripping Voltammetry
Last EEA report shows the importance of Water Framework Directive (WFD) to keep and improve waters quality in Europe
MONITOOL Project analyses its winter samples and obtains their first results
Sampling and sample processing and analysis WP5 protocols development
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DGT extraction and metal analysis by IFREMER

DGT extraction and metal analysis by IFREMER

The DGT technique is used to extract and concentrate metal cations in situ. Their use has shown that this approach is applicable for many metallic elements (Ag, Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn).

DGT resine recovery

Photo: DGT resine recovery – april 2018

DGT are very simple devices to implement. They irreversibly accumulate (on a Chelex 100 resin) the most "labile" dissolved metal cations (hydrated ions, mineral complexes, small organic complexes) depending on their concentration in the medium and the immersion time. The device consists of a plastic support, on which are arranged successively a phase for which the metal cations have a very strong affinity (Chelex 100 resin), a diffusion hydrogel of known thickness and a protective polycarbonate filter (Fig. 1&2). The metal cations migrate through the diffusion gel and settle irreversibly on the resin. It is the diffusion, controlled by the physical properties of the gel, temperature and metal concentration in the medium to be sampled, that determines the accumulation kinetics on the resin.

Diffusion of metal cations 

Figure 1: Photo of a DGT and operating principle

After recovery, the resin from each DGT is removed and eluted with nitric acid (1M). The eluate is analyzed by ICP-MS to determine the mass (M) of the various metallic elements accumulated in the resin.

Following the wet sampling campaign, most Monitool partners sent their DGT to Ifremer in April 2018. More than 150 DGTs were processed a few days after receipt (photo), then eluates were sent for ICP-MS analysis.

Cross section view of a DGT

Figure 2: Cross-section view of a DGT (the proportions are not respected)