Development and calibration of a passive sampler based on diffusive gels for monitoring of polar
organic compounds in water

Jakub Urík^1; Jitka Bečanová^1; Roman Grabic^2; Foppe Smedes^1; Branislav Vrana^1

^1Research Centre for Toxic Compounds in the Environment; Kamenice 753/5; 625 00 Brno; Czech
Republic

^2University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters;
Zátiší 728/II; 389 25 Vodňany; Czech Republic

urik@recetox.muni.cz



Passive sampling is nowadays commonly used technique for monitoring of trace contaminants in all
environmental matrices. In water, quantitative monitoring of polar compounds using adsorption-based
passive samplers poses a challenge, since non-isotropic exchange kinetics prevents effective use of
performance reference compounds (PRCs) commonly applied in partitioning-based samplers.
Concentrations of polar organic compounds in waters acquired by currently mostly used passive
samplers, such as POCIS, are semiquantitative, due to a strong dependence of uptake rates on the
variable hydrodynamic conditions and/or sorption of analytes to the membrane material separating
the sorbent from the aqueous phase. Sampling rates acquired by laboratory calibrations may
therefore differ from the actual sampling rates in the field. Recently, a novel sampler based on
DGT shows a great potential and has already been successfully used in sampling of different polar
compounds in waters and soils (Chen et al. 2012). In this so-called o-DGT sampler, the sorbent
containing gel is covered with a hydrogel diffusion layer that behaves as an immobilized water
layer. This layer may help to control the analyte uptake rate, eliminating the effect of
hydrodynamic conditions.

In our work, the applicability of agarose hydrogel has been tested for its suitability as a
diffusion medium for several pesticides, pharmaceuticals and perfluorinated compounds by measuring
analyte diffusion coefficients and their possible sorption to hydrogels. Then, using the o-DGT
design without a membrane, a laboratory uptake study has been conducted for broad spectrum of polar
substances, such as perfluorinated compounds, currently used pesticides and pharmaceuticals.
However, the sampling rates of a sampler design with an active surface area of 3.14 cm^2 turned out
to be too low for practical usage, therefore a new design was used, with an increased surface area
of 22,7 cm^2. A sorptive gel and diffusive gel layers strengthened by a nylon mesh netting are
enclosed between two metal rings, creating two sided gel-gel sampler with more than seven times
higher sampling area compared to o-DGT. This sampler design has been successfully tested on Svratka
River close to Brno, Czech Republic, alongside composite water sampling. Results of the field
testing prove that the novel design is suitable for monitoring of polar organic compounds in water.


References

Chen C.-E., Zhang H., and Jones K. C., A novel passive water sampler for in situ sampling of
antibiotics., J. Environ. Monit., 2012, 14, 1523–30.


Acknowledgements

The project (TB030MZP001/EMERTOX) received financial support from the Technology Agency of the
Czech Republic (TACR). The RECETOX research infrastructure was supported by the projects of the
Czech Ministry of Education (LO1214) and (LM2011028).