Iron Ion Sensor Based on Functionalized ZnO Nanorods, 2012, Electroanalysis

In this work, we are presenting an iron ion (Fe 3+ ) potentiometric sensor based on functionalized ZnO nanorods with selective ionophore (18 crown 6). Zinc oxide nanorods with a diameter of about 100 to 150 nm and 1μm in length were grown on gold coated glass. The selective Fe 3+ ionophore sensor with highly aligned ZnO nanorods has given high sensitivity, acceptable selectivity, reproducibility and stable signal response for detecting Fe 3+ . The potentiometric response of the Fe 3+ sensor with functionalized ZnO nanorods versus a Ag/AgCl reference electrode was observed to be linear over a logarithmic concentration range from 10 -5 M to 10 -2 M. The detection limit of the proposed sensor was about 5μM, which is lower than the normal blood concentration of Fe 3+ which is about 10μM and can be up to 30μM. The sensitivity of proposed Fe 3+ sensor was found to be 70.2±2.81 mV/decade with regression coefficient R 2 = 0.99 and a response time less than 5 seconds. The functionalized ZnO nanorods with selective iron ionophore has a life time greater than one month and has shown insignificant interference with other ions usually present in the human blood serum. The proposed sensor was used as an indicator electrode for potentiometric titration.