Heptadentate Schiff-base based PVC membrane sensor for Fe(III) ion determination in water samples

Tests performed using heptadentate Schiff's base ((tris(3-(thiophenal)propyl)amine (TTA)) toward Fe(III) ions indicated that it could be used as an Fe(III) selective ionophore to be used in a plasticized polymeric membrane sensor. The resulting sensors were found to produce a linear response range of five orders of magnitude with a slope of 19.8 ± 0.3 mV decade− 1 with a detection limit is 8.3 × 10− 9 mol L− 1. The sensor could be used in a pH window of 2.4–4.3 and the response time of the sensor was below 10 s, in addition to its very good Fe(III) selectivity over many mono-,di- and trivalent transition and heavy metal ions. The life time of the electrode was found to be at least 10 weeks.

► This work reports design of membrane sensor for the monitoring of iron in real samples.
► The novelty of this work is the high affinity of the ionophore toward the iron ions.
► The sensor is superior to the formerly reported Fe3+ sensors in terms of selectivity.