Highly selective sol-gel derived optical sensor using 2,6-dichlorophenolindophenol for the sensitive determination of aqueous iron(III)

The design and fabrication of a novel high-sensitivity optical sensor is reported that is highly selective for aqueous Fe3+. 2,6-Dichlorophenolindophenol is embedded in a film by the sol-gel method, which plays the role of the sensing element for Fe3+. The sensor selectively determined Fe(III) ion across a wide dynamic range from 1.70 x 10(-8) to 3.31 x 10(-3) M at pH 4.4 with a detection limit of 1.22 x 10(-8) M. The response of the sensor is fully reversible and is selective for Fe3+. The microporous nature of the stable sol-gel coating provides a unique optical membrane that gives reliable measurements. In addition, the sensor exhibits a long lifetime, long-term stability, and good repeatability. This sensor was successfully used to determine Fe3+ in tap and river water and showed satisfactory results.