Selective sensing of Fe³⁺ at pico-molar level with ethyl cellulose based electrospun nanofibers

In this work, a new procedure for the direct determination of picomolar levels of iron in water is presented. Ethyl cellulose (EC) based nano-fibers were fabricated by electrospinning technique. The limit of detection for Fe ³⁺ is 0.07 pM (based on 3 s of the blank, n = 4). A fluorescent chromoionophore and an ionic liquid were used together as sensing agent and signal stabilizer additives, respectively. The offered composite displayed a sensitive response for Fe³⁺ ions over a wide concentration range [1.0 × 10^-12-1.0 × 10^-6 M]. The sensing design exhibited a response time of less than 30 s which is one of the shortest reported responses among similar solid state sensing agents. The sensor was fully reversible and regeneration time was shorter than 60 s. Preliminary results show that sensitivity and selectivity of the nanofibrous membranes to detect Fe³⁺ ions are higher than those reported previously. Additionally, the exploited nanostructures provided faster sensor dynamics in applications.