Mn²⁺ selective electrode based on 3-(6-Aminopyridin-2-ylimino)-1, 3-diphenylpropylidene) pyridine-2, 6-diamine

The ion-selective electrode based on newly synthesized Schiff base 3-(6-aminopyridin-2-ylimino)-1, 3-diphenylpropylidene) pyridine-2, 6-diamine has been reported. Effect of various plasticizers; 2-nitrophenyloctylether (o-NPOE), dibutyl phosphonate (DBP), dioctylphthalate (DOP), tri-(2-ethylhexyl)phosphate (TEHP), chloronapthalin (CN), dibutyl butylphosphonate(DBBP) and anion excluder, Potassium tetrakis (p-chloropheny1)borate (KTpClPB) has been studied. The membrane with a composition of ionophore: KTpClPB : PVC : o-NPOE (w/w, mg ) in the ratio of 10 : 8 : 120 : 250 exhibited best performance. The sensor exhibits a working concentration range of 1.0 × 10^-6 - 1.0 × 10^-1 M with a detection limit of 4.0 × 10^-7 M and a Nernstian slope of 29.6 ±0.5mV decade^-1 activity in the pH range 4.0 to 8.0. The response time was as fast as < 15 s. The sensor has been found to work satisfactorily in partially non-aqueous media up to 10 % (v/v) content of methanol, ethanol, acetone or acetonitrile and could be used for a period of 3 months. The selectivity coefficients determined by using match potential method (MPM) and fixed interference method (FIM) indicated high selectivity for Mn²⁺. The application of prepared sensor has been demonstrated in determination of Mn (II) ions in spiked water samples and in some natural plant and edible species.