A novel potentiometric sensor for determination of fluoride ion based on ionophore N,N’-Ethylene-bis(salicylideneaminato) nickel (II)

Abstract

The N, N’-Ethylene-bis(salicylideneaminato) nickel(II) ionophore was synthesized and characterized by IR, NMR and C, H, N analysis. Polyvinyl chloride (PVC)-based membrane sensors of ionophore (I) with cation discriminator cetyl trimethylammonium bromide (CTAB) were prepared using different plasticizers such as dibutyl phthalate (DBP), dioctyl phthalate (DOP), 1-chloronaphthalene (CN), and tri-n-butylphosphate (TBP). Among the several membrane sensors prepared, the one having membrane composition in the ratio of 1: 33: 65: 1 mg (I: PVC: DBP: CTAB) showed best performance. This sensor performed well over a wide concentration range of 5.9 × 10−6–1.0 × 10−1 M with a detection limit of 3.6 × 10−6 M and slope of 57.2 ± 0.2 mV per decade. The proposed sensor can be used in the wide pH range (2.1–9.1) and showed a quick response time of 22 s. The selectivity coefficient values calculated using the fixed interference technique (FIM) exhibit that the sensor has good selectivity for fluoride ions over a large variety of anions. The sensor showed a shelf life of 50 days and during this period the results were highly reproducible. The sensor was successfully utilized for the detection of fluoride ions in drinking water and tea sample.