The Diffusive Gradient in Thin-films (DGT) technique has been developed in the 1990’s with field applications that were initially limited to measuring some transition metals at trace levels in aquatic environments. Since then, a very active community of researchers have progressively created numerous binding gels with different selectivity permitting to cover almost all elements of the periodic table. However, for some elements like uranium, binding gels able to accumulate U(VI) in all types of media (river waters, sea water, soils, sediments) are still not available. Among the sixteen DGT methods developed so far for UO22+, the commercially available samplers containing either the Chelex-100 resin (polystyrene matrix functionalized with iminodiacetic acid chelating groups) or Metsorb material (TiO2-based adsorbent) are the most employed. Depending on the deployment conditions, their performances to determine the labile U(VI) concentration in aquatic environment can be unsatisfactory because these DGT samplers are not selective to UO22+ and the binding sites may become saturated by competing ions.1,2 In this study, we propose to improve the DGT sampling of labile UO22+ species by employing a new strategy that relies on the knowledge of the U coordination chemistry and the development of ligands targeted for this specific element. New binding agents, including a siderophore, with strong complexation capacity for iron and actinides3–5 were grafted on a carboxylic resin and incorporated in an agarose hydrogel for their use in DGT samplers. Laboratory validation experiments were performed in simple solutions (10 mmol L–1 NaNO3 and 1 mmol L–1 NaHCO3), in which the prevailing U(VI) species are [UO2(CO3)3]4– and [UO2(CO3)2]2–. Then, time-series experiments were performed in complex matrices in which additional U(VI) species are present (i.e., Ca2UO2(CO3)3, [CaUO2(CO3)3]2–, [MgUO2(CO3)3]2– and/or [UO2(CO3)3]4–). After evaluating the DGT performances in the laboratory, a field test was finally performed in the Essonne River (Essonne, France). Results for the siderophore-based DGT sampler are compared to measurements performed with Chelex- and Metsorb-DGT samplers both in lab and in field.