A Novel Iron(III) Selective Membrane Electrode Containing a Tripodal Polycatacholamine as Sensor

摘要

A novel poly(vinylchloride)-based membrane sensor using N1,N3,N5-tris(2-(2,3-dihydroxybenzylamino)- ethyl)cyclohexane-1,3,5-tricarboxamide (CYCOENCAT, L) as ionophore has been prepared and explored as Fe3+ selective electrode. The membrane electrode composed of ionophore, poly(vinylchloride) and o-nitropheyloctyl ether in the optimum ratio 4:33:63 gave excellent potentiometric response characteristics, and displayed a linear log[Fe3+] versus EMF response over a wide concentration range of 1.0 × 10−5 - 1.0 × 10−1 M with super nernstian slope of 28.0 mV/decade and the detection limit of 8.0 × 10−6 M. The proposed ion selective electrode showed fast response time ( 15 s), wide pH range (3.0-7.0), high non-aqueous tolerance (up to 20%) and adequate long life time (120 days). It also exhibited very good selectivity for Fe3+ relative to a wide variety of alkali, alkaline earth, transition and heavy metal ions. Further, the analytical applicability of the sensor was tested as an indicator electrode in the potentiometric titration of Fe3+ with EDTA.