Availability of metals to DGT devices with different configurations. The case of sequential Ni complexation

The analytical technique DGT (Diffusive Gradients in Thin-films) is able to gain access a wealth of information by carefully interpreting accumulation data from passive samplers with different configurations (i.e. thicknesses its constituent layers). A set devices were simultaneously deployed solutions Ni and nitrilotriacetic acid (NTA) concentrations measure the availability these solutions. Accumulations indicate that depends on both thickness resin diffusive gel. In cases, lability degree increases as increases. As formation successive complexes (such Ni(NTA)2) proceeds, metal decreases, which quantitatively explained reducing formulation case only one complex, but an effective dissociation rate constant decreases concentration NTA Simple expressions are reported quantify configurations. These results can characterize cation natural sample uptake processes at spatial or time scales. Alternatively, more fundamental point view, speciation, mobilities labilities species present samples be obtained