A Novel Iron Optical Sensor Based on 2-(2-Benzothiazolylazo)Phenol Polymer Inclusion Membrane

The use of a polymer inclusion membrane (PIM) as a sensing material is a novel approach to overcome the selectivity and stability of the optical chemical sensor (optode). In this work, non-plasticized PIM containing poly vinyl chloride (PVC) as a support base, 2-(2-benzothiazolylazo)phenol (BTAP)  as a reagent and Aliquat 336 as a fixed carrier (ionophore) was prepared and its performance was tested for application in an optode to determine Fe3+‏ ions. The results showed that PIM properties are greatly affected by the membrane composition. The studies revealed that the optode response was dependent on film thickness, the presence of plasticizer, stirring effect, concentration of BTAP, concentration of Aliquat 336 and pH of the aqueous solution used. A linear calibration curve in the range from 5.0–210 ng mL−1 of Fe3+, with a detection and quantification limits of 1.60 and 4.95 ng mL−1, respectively were obtained. The maximum wavelength (λmax) for the PIM based optical optode was 581 nm. The PIM developed in this investigation was found to be stable, has good mechanical strength, sensitive and reusable. Lastly, the PIM was successfully applied as an optical sensor to determine Fe3+ ions in natural water, food, biological and environmental samples, and the obtained result is comparable to atomic absorption spectrometry method.