The high phosphorus as phosphate input into aquatic systems causes eutrophication which leads to the occurrence of algae blooming. Phosphate input in aquatic systems is influenced by the release of suspected phosphate bound to iron(III) when reduced to iron(II) in the sediment. Diffusive gradients in thin films (DGT) technique is one of the in-situ measurement methods developed for the measurement of phosphate and metals. DGT technique was studied using gel bindings mixture of TiO2-Chelex. This new method introduces the use synthesis of TiO2 via sol-gel method and resin Chelex-100 as phosphate and iron(II) binding agents, respectively. DGT composed of diffusive and binding layer was tested for their ability to absorb iron(II) and phosphate separately, and homogeneity. DGT with bindings TiO2-Chelex gel was tested at various measurement time, solution concentration, and pH. The results of the analysis using AAS for iron and UV - Vis spectrophotometer for phosphate showed that the optimum time for DGT measurement is 24 hours. Optimum measurement of DGT with bindings gel TiO2-Chelex was reached at pH around pH 5.2 and 6 for phosphate, and neutral (pH 7) for iron(II). TiO2-Chelex DGT measurement capacity was 5.86mg/L and 53.41 mg/L for phosphate and iron (II), respectively. In conclusion, the TiO2-Chelex mixed binding gel that was made can absorb iron (II) and phosphate simultaneously.