Diffusive equilibration in thin films uses devices similar to DGT, but there is no binding gel. It uses an open pore diffusive gel, which is mainly water. Solutes in the adjacent medium are allowed to establish equilibrium with the solutes in the diffusive gel.
Its main use is for measuring solutes in the pore-waters of sediments. Vertical diffusion within the gel can be prevented, by using probes comprising recessed slots filled with gel. With these “constrained” probes a vertical spatial resolution of 2 mm is typically achieved.