A novel Mg(II)-selective sensor based on 5,10,15,20-tetrakis(2-furyl)-21,23-dithiaporphyrin as an electroactive material

A novel poly(vinyl chloride) based membrane containing 5,10,15,20-tetrakis(2-furyl)-21,23-dithiaporphyrin (I) as an electroactive material along with sodiumtetraphenylborate (NaTPB), and nitrophenyl octyl ether (NPOE) in the ratio 10:100:1:150 (I:NPOE:NaTPB:PVC) (w/w) was used to fabricate a Mg(II)-selective sensor. The developed sensor exhibits a wide working concentration range of 9.2 × 10−6–1.0 × 10−1 M, with a Nernstian slope of 30.0 ± 1.0 mV/decade of activity and the response time of 15 s. This sensor shows a detection limit of 8.0 × 10−6 M. Its potential response remains unaffected of pH in the range 4.0–8.4, and the cell assembly can be successfully used in partially non-aqueous medium (up to 10% v/v) without any significant change in the slope or working concentration range. The sensor has a lifetime of about 8 weeks and exhibits excellent selectivity over a number of mono-, bi-, and tri-valent cations including alkali, alkaline earth metal, heavy and transition metal ions. It has also been used for the determination of magnesium ion concentration in real samples.