Particle extraction via the liquid-liquid interface (PELLI) method has been utilized to produce Di-(2-ethylhexyl) phosphate (DEHP) coated MnO2 fluorescent nanoprobe denoted as MnO2@DEHP for the selective detection of Fe3+ ions. The synthesized MnO2@DEHP nanoprobe was characterized by various instrumental techniques such as FT-IR, PXRD, TEM, EDAX, HRTEM, DLS, and XPS. Since the high concentration of Fe3+ in waste water leads to water pollution, which in turn affects the ecosystem, and causes severe health hazards. Therefore, accurate detection of Fe3+ ions in the aqueous systems is essential as they are involved in various chemical and biological processes in living things. Here, the synthesized MnO2@DEHP nanoprobe selectively detects Fe3+ ions in the presence of various metal ions in an aqueous media by fluorescence quenching (turn-off) mechanism. The limit of detection (LOD) of MnO2@DEHP nanoprobe for Fe3+ was found to be 0.49µM. The test-strip method and real water sample analysis were also used to demonstrate the viability of MnO2@DEHP as a fluorescent nanoprobe to detect Fe3+ ions visually and in environment monitoring applications.